Issue 1:
Hi,

As described in this issue, when I run cargo test I receive this output:

FAILED (errors=1)
', cli/tests/util/mod.rs:34:5
stack backtrace:
0: backtrace::backtrace::libunwind::trace
at /Users/vsts/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/libunwind.rs:88
1: backtrace::backtrace::trace_unsynchronized
at /Users/vsts/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/mod.rs:66
2: std::sys_common::backtrace::_print
at src/libstd/sys_common/backtrace.rs:47
3: std::sys_common::backtrace::print
at src/libstd/sys_common/backtrace.rs:36
4: std::panicking::default_hook::{{closure}}
at src/libstd/panicking.rs:200
5: std::panicking::default_hook
at src/libstd/panicking.rs:211
6: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:477
7: std::panicking::continue_panic_fmt
at src/libstd/panicking.rs:384
8: std::thread::local::fast::Key<T>::try_initialize
9: integration_tests::util::run_python_script
at cli/tests/util/mod.rs:34
10: integration_tests::fmt_test
at cli/tests/integration_tests.rs:32
11: integration_tests::fmt_test::{{closure}}
at cli/tests/integration_tests.rs:30
12: core::ops::function::FnOnce::call_once
at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libcore/ops/function.rs:235
13: <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once
at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/liballoc/boxed.rs:787
14: __rust_maybe_catch_panic
at src/libpanic_unwind/lib.rs:80
15: std::panicking::try
at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libstd/panicking.rs:275
16: std::panic::catch_unwind
at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libstd/panic.rs:394
17: test::run_test::run_test_inner::{{closure}}
at src/libtest/lib.rs:1408
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

---- js_unit_tests stdout ----
thread 'js_unit_tests' panicked at 'called `Result::unwrap()` on an `Err` value: "PoisonError { inner: .. }"', src/libcore/result.rs:1084:5
stack backtrace:
0: backtrace::backtrace::libunwind::trace
at /Users/vsts/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/libunwind.rs:88
1: backtrace::backtrace::trace_unsynchronized
at /Users/vsts/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/mod.rs:66
2: std::sys_common::backtrace::_print
at src/libstd/sys_common/backtrace.rs:47
3: std::sys_common::backtrace::print
at src/libstd/sys_common/backtrace.rs:36
4: std::panicking::default_hook::{{closure}}
at src/libstd/panicking.rs:200
5: std::panicking::default_hook
at src/libstd/panicking.rs:211
6: std::panicking::rust_panic_with_hook
at src/libstd/panicking.rs:477
7: std::panicking::continue_panic_fmt
at src/libstd/panicking.rs:384
8: rust_begin_unwind
at src/libstd/panicking.rs:311
9: std::panicking::begin_panic
10: std::panicking::begin_panic
11: core::result::Result<T,E>::unwrap
at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libcore/result.rs:852
12: deno_cli::test_util::http_server
at cli/test_util.rs:62
13: integration_tests::js_unit_tests
at cli/tests/integration_tests.rs:38
14: integration_tests::js_unit_tests::{{closure}}
at cli/tests/integration_tests.rs:37
15: core::ops::function::FnOnce::call_once
at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libcore/ops/function.rs:235
16: <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once
at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/liballoc/boxed.rs:787
17: __rust_maybe_catch_panic
at src/libpanic_unwind/lib.rs:80
18: std::panicking::try
at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libstd/panicking.rs:275
19: std::panic::catch_unwind
at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libstd/panic.rs:394
20: test::run_test::run_test_inner::{{closure}}
at src/libtest/lib.rs:1408
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

My cargo --version is cargo 1.38.0 (23ef9a4ef 2019-08-20) & rustc --version is rustc 1.38.0 (625451e37 2019-09-23).

I also get this error earlier in the format test (python2 tools/format.py passes) and that is where the panic occurs:

Traceback (most recent call last):
File "tools/fmt_test.py", line 31, in test_fmt
quiet=True)
File "/Users/usrname/Documents/deno/tools/util.py", line 99, in run_output
sys.exit(retcode)
SystemExit: -4

I don't know enough about the logic of util.py to know why this is being thrown from L99 but it's in the run_output function.

Issue 2:
🙁

tmnk@buildDeno:~/deno$ ./target/debug/deno fmt badly_formatted.js
Download https://deno.land/std@8c90bd9/prettier/vendor/standalone.js
Download https://deno.land/std@8c90bd9/prettier/vendor/parser_typescript.js
Download https://deno.land/std@8c90bd9/prettier/vendor/parser_markdown.js

#
# Fatal error in ../../core/libdeno/v8/src/parsing/preparser.h, line 1076
# Debug check failed: !parsing_module_.
#
#
#
#FailureMessage Object: 0x7eff75515cc0
==== C stack trace ===============================

./target/debug/deno(+0x286acb3) [0x55aadeed1cb3]
./target/debug/deno(+0x273e52b) [0x55aadeda552b]
./target/debug/deno(+0x1e6e648) [0x55aade4d5648]
./target/debug/deno(+0x1e6e375) [0x55aade4d5375]
./target/debug/deno(+0x1adf30f) [0x55aade14630f]
./target/debug/deno(+0x1a7927e) [0x55aade0e027e]
./target/debug/deno(+0x1a7b081) [0x55aade0e2081]
./target/debug/deno(+0x1a7abd0) [0x55aade0e1bd0]
./target/debug/deno(+0x1ad1346) [0x55aade138346]
./target/debug/deno(+0x1acf856) [0x55aade136856]
./target/debug/deno(+0x1ad6f14) [0x55aade13df14]
./target/debug/deno(+0x1ad68a6) [0x55aade13d8a6]
./target/debug/deno(+0x1ad4ee4) [0x55aade13bee4]
./target/debug/deno(+0x1ad63f0) [0x55aade13d3f0]
./target/debug/deno(+0x1ad4fea) [0x55aade13bfea]
./target/debug/deno(+0x1ad2753) [0x55aade139753]
./target/debug/deno(+0x1adf556) [0x55aade146556]
./target/debug/deno(+0x1addc1e) [0x55aade144c1e]
./target/debug/deno(+0x1a7927e) [0x55aade0e027e]
./target/debug/deno(+0x1a7b081) [0x55aade0e2081]
./target/debug/deno(+0x1a7abd0) [0x55aade0e1bd0]
./target/debug/deno(+0x1ad1346) [0x55aade138346]
./target/debug/deno(+0x1acf856) [0x55aade136856]
./target/debug/deno(+0x1ad6f14) [0x55aade13df14]
./target/debug/deno(+0x1ad68a6) [0x55aade13d8a6]
./target/debug/deno(+0x1ad4ee4) [0x55aade13bee4]
./target/debug/deno(+0x1ad45b4) [0x55aade13b5b4]
./target/debug/deno(+0x1aced95) [0x55aade135d95]
./target/debug/deno(+0x1ad6f78) [0x55aade13df78]
./target/debug/deno(+0x1ad68a6) [0x55aade13d8a6]
./target/debug/deno(+0x1ad4ee4) [0x55aade13bee4]
./target/debug/deno(+0x1ad63f0) [0x55aade13d3f0]
./target/debug/deno(+0x1adb37b) [0x55aade14237b]
./target/debug/deno(+0x1acc833) [0x55aade133833]
./target/debug/deno(+0x1a7927e) [0x55aade0e027e]
./target/debug/deno(+0x1a7b081) [0x55aade0e2081]
./target/debug/deno(+0x1a7abd0) [0x55aade0e1bd0]
./target/debug/deno(+0x1ad1346) [0x55aade138346]
./target/debug/deno(+0x1acf856) [0x55aade136856]
./target/debug/deno(+0x1ad6f14) [0x55aade13df14]
./target/debug/deno(+0x1ad68a6) [0x55aade13d8a6]
./target/debug/deno(+0x1ad4ee4) [0x55aade13bee4]
./target/debug/deno(+0x1ad45b4) [0x55aade13b5b4]
./target/debug/deno(+0x1aced95) [0x55aade135d95]
./target/debug/deno(+0x1ad6f78) [0x55aade13df78]
./target/debug/deno(+0x1ad68a6) [0x55aade13d8a6]
./target/debug/deno(+0x1ad4ee4) [0x55aade13bee4]
./target/debug/deno(+0x1ad63f0) [0x55aade13d3f0]
./target/debug/deno(+0x1adb37b) [0x55aade14237b]
./target/debug/deno(+0x1acc833) [0x55aade133833]
./target/debug/deno(+0x1a7927e) [0x55aade0e027e]
./target/debug/deno(+0x1a7a423) [0x55aade0e1423]
./target/debug/deno(+0x1a798e0) [0x55aade0e08e0]
./target/debug/deno(+0x284c271) [0x55aadeeb3271]
./target/debug/deno(+0x284155b) [0x55aadeea855b]
./target/debug/deno(+0x2859c4d) [0x55aadeec0c4d]
./target/debug/deno(+0x2858284) [0x55aadeebf284]
./target/debug/deno(+0x2856a34) [0x55aadeebda34]
./target/debug/deno(+0x2855e46) [0x55aadeebce46]
./target/debug/deno(+0x28548e0) [0x55aadeebb8e0]
./target/debug/deno(+0x285bf35) [0x55aadeec2f35]
./target/debug/deno(+0x2857615) [0x55aadeebe615]
Illegal instruction (core dumped)

tmnk@buildDeno:~/deno$ cat badly_formatted.js

console.log(
"Hello World"
)

tmnk@buildDeno:~/deno$ cat /proc/version
Linux version 5.0.0-1018-azure (buildd@lgw01-amd64-048) (gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1)) #19~18.04.1-Ubuntu SMP Wed Aug 21 05:13:05 UTC 2019