roachtest: add test_create_symbol_fixtures to ActiveRecord ignore list

The test CockroachDB::FixturesTest#test_create_symbol_fixtures is flaky
and should be ignored in the activerecord test suite.

Closes #155304

Release note: none

Author: spilchen

pkg/cmd/roachtest/tests/activerecord_blocklist.go

@@ -38,6 +38,7 @@ var activeRecordIgnoreList = blocklist{
 	`CockroachDB::AdapterForeignKeyTest#test_foreign_key_violations_on_delete_are_translated_to_specific_exception`:                                            "flaky",
 	`CockroachDB::AdapterForeignKeyTest#test_foreign_key_violations_on_insert_are_translated_to_specific_exception`:                                            "flaky",
 	`CockroachDB::FixturesTest#test_create_fixtures`:                                                                                                           "flaky",
+	`CockroachDB::FixturesTest#test_create_symbol_fixtures`:                                                                                                    "flaky",
 	`FixtureWithSetModelClassPrevailsOverNamingConventionTest#test_model_class_in_fixture_file_is_respected`:                                                   "flaky",
 	`HasManyAssociationsTest#test_collection_association_with_private_kernel_method`:                                                                           "flaky",
 	`HasManyAssociationsTest#test_delete_all_association_with_primary_key_deletes_correct_records`:                                                             "flaky",