message: [XLA] Don't crash in the verifier if an operand's parent is null
diff: @@ -1324,7 +1324,8 @@ Status VerifyHloStructure(HloModule* module) {
  "Operand %d (%s) of instruction %s is in a different "
  "computation: %s vs %s",
  i, operand->name(), instruction->name(),
  - operand->parent()->name(), instruction->parent()->name());
  + operand->parent() ? operand->parent()->name() : "(null)",
  + instruction->parent()->name());
  }
  }
  }
  