Moved the check for the rails test environment into rails/test_unit so that you
can select frameworks separately when running rake test.
Merge pull request #10256 from wangjohn/moving_check_for_test_environment_into_rails_env

Moved the check for the rails test environment into rails.rb

Closes #10238
Remove code duplication
Merge pull request #10331 from neerajdotname/exec-migration-in-transaction

Remove code duplication
Testcase for #10066. Serialized or time zone aware attributes should not be wrapped twice.
Fix a SystemStackError that occurs when using time zone aware attributes.

This fixes issue #10066
Add a CHANGELOG entry about #10066.