message: Add comment about observed test flake
diff: @@ -523,6 +523,9 @@ void FileSystemTest::TestLockBumping() {
  // Try to take the lock again. If bumping didn't work, then the lock would
  // have expired 1s ago and we could have taken it here.
  + // TODO(oschaaf): I have observed this flaking a single time during release
  + // test execution. We should look into bumping the timeouts here if it happens
  + // again.
  EXPECT_FALSE(file_system()->TryLockWithTimeout(
  lock_name, Timer::kSecondMs * 3, timer(), &handler_).is_true());
  