Unignore a few tests

Also, remove one that has an exact duplicate.
libstd: Inline more methods on bitflags.

Servo really wants this.
Add tests for a few fixed issues
auto merge of #18103 : pcwalton/rust/bitflags-inline, r=thestinger

Servo really wants this.

r? @nick29581
auto merge of #18099 : jakub-/rust/fixed-issues, r=alexcrichton

Closes #9249.
Closes #13105.
Closes #13837.
Closes #13847.
Closes #15207.
Closes #15261.
Closes #16048. 
Closes #16098.
Closes #16256.
Closes #16562.
Closes #16596.
Closes #16709.
Closes #16747.
Closes #17025.
Closes #17121.
Closes #17450.
Closes #17636.
debuginfo: Gate all LLDB debuginfo tests on a minimum LLDB version being available
debuginfo: Make some path LLDB-related paths in the test runner absolute to help the build bots.
debuginfo: Enable LLDB test suite on Darwin.
debuginfo: Let LLDB tests run in parallel again since our min-supported version has no problems with that.