message: Fix pass pipeline round-tripping for xla-legalize-tf.
  It now prints out correctly as `xla-legalize-tf{allow-partial-conversion=true}` or `xla-legalize-tf{allow-partial-conversion=false}` instead of just `xla-legalize-tf`.
diff: @@ -71,6 +71,12 @@ class LegalizeTF : public FunctionPass<LegalizeTF> {
  /// Performs the lowering to XLA dialect.
  void runOnFunction() override;
  + /// Print this pass for a textual pipeline. It must round-trip.
  + void printAsTextualPipeline(raw_ostream &os) override {
  + os << "xla-legalize-tf{allow-partial-conversion="
  + << (allow_partial_conversion_ ? "true" : "false") << "}";
  + }
  +
  private:
  bool allow_partial_conversion_;
  };
  