Reset column info after making Topic tz-aware

[gmcgibbon]

Fixes #35194.

This is a really strange bug.

For some reason, .reload_schema_from_cache called by Topic.reset_column_information can change how date time columns behave. It seems to change included modules of ActiveRecord::Type::DateTime instances, but only sometimes.

In the expected flow, the value cast starts here and includes [ActiveRecord::Type::Internal::Timezone, #<ActiveModel::Type::Helpers::AcceptsMultiparameterTime:0x00007f8cae260358>, ActiveModel::Type::Helpers::TimeValue, ActiveSupport::ToJsonWithActiveSupportEncoder, ActiveSupport::Dependencies::Loadable, JSON::Ext::Generator::GeneratorMethods::Object, ActiveSupport::Tryable, Kernel]. In the failing test case, the value cast starts here and includes [ActiveSupport::Tryable, #<Module:0x00007f8b010f1e58>].

This seems to be triggered by initializing a new topic in AttributeMethodsTest#test_YAML_dumping_a_record_with_time_zone-aware_attribute after resetting column info in a previous test. My proposed solution is more of a band-aid to minimize the blast radius of attribute changes between tests (this was already being done for other tests in AttributeMethodsTest).

[gmcgibbon]

This seems to break other time related tests strangely, I will continue to investigate.

I should mention too that this is not specific to MySQL. You can reproduce the problem with any adapter:

bin/test test/cases/serialized_attribute_test.rb test/cases/attribute_methods_test.rb test/cases/base_test.rb -n "/^(?:SerializedAttributeTest#(?:test_serialize_does_not_eagerly_load_columns)|AttributeMethodsTest#(?:test_YAML_dumping_a_record_with_time_zone-aware_attribute)|BasicsTest#(?:test_preserving_time_objects_with_time_with_zone_conversion_to_default_timezone_local))$/" --seed 17411 -v

[gmcgibbon]

It turns out this line initializes a Topic with time_zone_aware_attributes enabled, which causes the date time attribute differences. We need to use a global class here because of how YAML dumping/loading works (other tz-aware column tests don't use the global Topic class). I've opted to simply reset column info on Topic after the test to tell Active Record to forget about the attribute change.