Introduces "ANGLE_NO_SANITIZE_THREAD" which works the same way as
"ANGLE_NO_SANITIZE_MEMORY".

Bug: chromium:1223970
Change-Id: I9409771f7c4748bbc186da3fc38031d3b1d1e4d8
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2987875
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>