[compiler-rt] [TSan] Fix spurious 'thread finished with ignores enabled' warning on FreeBSD (PR #155399)

[Evan Wilde via llvm-commits]

https://github.com/etcwilde approved this pull request.

This fixes the issue I was running into. I'm a little worried that this doesn't seem to fix or break any LLVM tests though, or if this interceptor was just untested to begin with.

Given that `DestroyThreadState` verifies that the thread is not being ignored and the scoped interceptor marks the thread ignored and is still alive when `DestroyThreadState` is called, I'm not sure how this ever worked either. Someone more familiar with the scoped interceptor and TSan should probably approve before merging, but otherwise LGTM.

https://github.com/llvm/llvm-project/pull/155399