Update kernel appup test to work for OTP release 17
erts/kernel: sendfile no longer uses async threads

This has been done because a slow client attack is possible if the
async thread pool is used. The scenario is:

Client does a request for a file and then slowly receives the file one
byte at a time. This will eventually fill the async thread pool with blocking
sendfile operations and thus starving the vm of all file operations.

If you still want to use the async threads pool for sendfile an option to
enable it has been introduced.
erts: fix bug when using passive mode and sendfile

The bug incorrectly issued driver_select when un-ignoring an fd
for a socket in passive mode, which caused an incorrect error
tuple to be returned when the remote end closed the connection.
Merge branch 'lukas/erts/sendfile_passive_mode_fix/OTP-11614'

* lukas/erts/sendfile_passive_mode_fix/OTP-11614:
  erts: fix bug when using passive mode and sendfile
Merge branch 'siri/appup_tests_17/OTP-11534'

* siri/appup_tests_17/OTP-11534:
  Update sasl appup test to work for OTP release 17
  Update stdlib appup test to work for OTP release 17
  Update kernel appup test to work for OTP release 17
Change the default file name encoding mode to +fnaw
Merge branch 'lukas/erts/sendfile_no_async_pool/OTP-11639'

* lukas/erts/sendfile_no_async_pool/OTP-11639:
  erts/kernel: sendfile no longer uses async threads
Merge branch 'bjorn/fna-default/OTP-11612'

* bjorn/fna-default/OTP-11612:
  Change the default file name encoding mode to +fnaw
Make the references to various Erlang/OTP releases verbose
Allow persistent option on set_env/4 and unset_env/3

An environment key set with the persistent option will not
be overridden by the ones configured in the application resource
file on load. This means persistent values will stick after the
application is loaded and also on application reload.
Update appups and appup tests for kernel, stdlib and sasl

Appups now only support one major release back, and the tests are
updated accordingly.

Support is also added in tests for giving previous releases in a ct
config file, e.g.

{otp_releases,[{r15,"/path/to/r15/bin/erl"},
	       {r16,"/path/to/r16/bin/erl"},
	       {'17',"/path/to/17/bin/erl"}]}.
Fix a few of Dialyzer's unmatched_return warnings
Merge branch 'josevalim/jv-persistent-set-env'

* josevalim/jv-persistent-set-env:
  Allow persistent option on set_env/4 and unset_env/3

OTP-11708
kernel: Fix an application terminate deadlock possibility

Could happen if get_child was called during terminate.
io (since it is a group_leader) also causes problems after
get_child was called.

Split up and do it async.
Correct the contract of inet:ntoa/1

Thanks to Max Treskin.
Merge branch 'siri/appup_tests_17/OTP-11534'

* siri/appup_tests_17/OTP-11534:
  Update sasl/test/test_lib.hrl with recent versions of kernel and stdlib
  Update appups and appup tests for kernel, stdlib and sasl
Merge branch 'hb/kernel/spec_bug_fix/OTP-11730'

* hb/kernel/spec_bug_fix/OTP-11730:
  Correct the contract of inet:ntoa/1
Unload 'deadlock' application in application_SUITE:shutdown_deadlock

This is just to clean up properly after the test case. If not,
code_SUITE:bit_boot_embedded might fail since it tries to include the
'deadlock' application in the boot file and fails when running
systools:make_script.
Use default timetrap (30 min) for kernel, stdlib and sasl app tests

These tests start new nodes, and they frequently timed out on some
slow test hosts.
Deprecate pre-defined built-in types

The types array(), dict(), digraph(), gb_set(), gb_tree(), queue(),
set(), and tid() have been deprecated. They will be removed in OTP 18.0.

Instead the types array:array(), dict:dict(), digraph:graph(),
gb_set:set(), gb_tree:tree(), queue:queue(), sets:set(), and ets:tid()
can be used. (Note: it has always been necessary to use ets:tid().)

It is allowed in OTP 17.0 to locally re-define the types array(), dict(),
and so on.

New types array:array/1, dict:dict/2, gb_sets:set/1, gb_trees:tree/2,
queue:queue/1, and sets:set/1 have been added.