Added a test that verifies that waiting for a condition variable actually waits for a non-zero time. This used to fail due to a TSAN / CLANG bug, but this failure is supposed to have been fixed. This was originally https://webrtc-codereview.appspot.com/2145004 BUG=2259 Review URL: https://codereview.webrtc.org/1416873002 Cr-Commit-Position: refs/heads/master@{#10341}