message: Set column to 0 to avoid ubsan failure.
  Avoids index expression overflow due to subtraction between fake location pointer and column in SourceMgr.cpp#440.
  Quite possibly if the file is not registered, the FixItLine should not be created. But fixing ubsan directly first.
diff: @@ -29,12 +29,8 @@ using testing::HasSubstr;
  TEST(ErrorUtilTest, StatusScopedDiagnosticHandler) {
  MLIRContext context;
  -
  - auto emit_error = [&](const std::string& msg) {
  - emitError(FileLineColLoc::get(Identifier::get("test.cc", &context), 10, 32,
  - &context),
  - msg);
  - };
  + auto id = Identifier::get("test.cc", &context);
  + auto loc = FileLineColLoc::get(id, 0, 0, &context);
  // Test OK without diagnostic gets passed through.
  {
  @@ -44,7 +40,7 @@ TEST(ErrorUtilTest, StatusScopedDiagnosticHandler) {
  // Verify diagnostics are captured as Unknown status.
  {
  StatusScopedDiagnosticHandler handler(&context);
  - emit_error("Diagnostic message");
  + emitError(loc) << "Diagnostic message";
  ASSERT_TRUE(tensorflow::errors::IsUnknown(handler.ConsumeStatus()));
  }
  @@ -58,8 +54,8 @@ TEST(ErrorUtilTest, StatusScopedDiagnosticHandler) {
  // Verify diagnostic reported are append to passed in error.
  {
  auto function = [&]() {
  - emit_error("Diagnostic message reported");
  - emit_error("Second diagnostic message reported");
  + emitError(loc) << "Diagnostic message reported";
  + emitError(loc) << "Second diagnostic message reported";
  return tensorflow::errors::Internal("Passed in error");
  };
  Status s = StatusScopedDiagnosticHandler(&context).Combine(function());
  