Suppress TSan errors triggered when deadlock detection is enabled.

These are problematic when running with the default TSan
settings which has deadlock detection enabled.
Our bots still run with it disabled but we want to be
able to turn it back on, thus this is needed.

BUG=3911,4456
TESTED=
Successfully executed:
GYP_DEFINES="tsan=1 release_extra_cflags=-g use_allocator=none" webrtc/build/gyp_webrtc
ninja -C out/Release rtc_unittests
out/Release/rtc_unittests

R=pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/44899004

Cr-Commit-Position: refs/heads/master@{#8879}
1 file changed