message: [TF:XLA] make miscomparison error messages more readable
diff: @@ -716,9 +716,11 @@ Status Equal(const LiteralSlice& expected, const LiteralSlice& actual) {
  }
  return AppendStatus(result,
  - tensorflow::strings::Printf("expected: %s\nactual: %s",
  - expected.ToString().c_str(),
  - actual.ToString().c_str()));
  + tensorflow::strings::Printf(
  + "\nat index: %s\nexpected: %s\nactual: %s",
  + Literal::MultiIndexAsString(multi_index).c_str(),
  + ToStringTruncated(expected).c_str(),
  + ToStringTruncated(actual).c_str()));
  }
  Status Near(const LiteralSlice& expected, const LiteralSlice& actual,
  