message: Pass -v when invoking FileCheck.
  FileCheck has learned to output the debugging information we were printing, plus other info.  See
diff: @@ -48,7 +48,7 @@ StatusOr<bool> RunFileCheck(const string& input, const string& pattern) {
  tensorflow::SubProcess file_check_process;
  file_check_process.SetProgram(file_check_path,
  - {file_check_path, pattern_path});
  + {file_check_path, "-v", pattern_path});
  file_check_process.SetChannelAction(tensorflow::CHAN_STDIN,
  tensorflow::ACTION_PIPE);
  file_check_process.SetChannelAction(tensorflow::CHAN_STDERR,
  @@ -71,9 +71,7 @@ StatusOr<bool> RunFileCheck(const string& input, const string& pattern) {
  LOG(WARNING) << "NOTE: FileCheck binary does not exist!";
  }
  - LOG(WARNING) << "FileCheck error: " << standard_error;
  - LOG(WARNING) << "FileCheck input was:";
  - XLA_LOG_LINES(tensorflow::WARNING, input);
  + LOG(WARNING) << "FileCheck error:\n" << standard_error;
  LOG(WARNING) << "FileCheck pattern was:";
  XLA_LOG_LINES(tensorflow::WARNING, pattern);
  } else if (!standard_error.empty()) {
  