message: Print FileCheck failures as LOG(WARNING).
  Previously they were VLOG'ed, which meant that if you had a failing
  test, you'd have to rerun it with special flags in order to see what's
  going on.
diff: @@ -66,11 +66,11 @@ StatusOr<bool> RunFileCheck(const string& input, const string& pattern) {
  // the error message generated by FileCheck and the inputs.
  bool succeeded = (exit_status == 0);
  if (!succeeded) {
  - VLOG(1) << "FileCheck error: " << standard_error;
  - VLOG(1) << "FileCheck input was:";
  - XLA_VLOG_LINES(1, input);
  - VLOG(1) << "FileCheck pattern was:";
  - XLA_VLOG_LINES(1, pattern);
  + LOG(WARNING) << "FileCheck error: " << standard_error;
  + LOG(WARNING) << "FileCheck input was:";
  + XLA_LOG_LINES(tensorflow::WARNING, input);
  + LOG(WARNING) << "FileCheck pattern was:";
  + XLA_LOG_LINES(tensorflow::WARNING, pattern);
  }
  return succeeded;
  }
  