Fix CI failure due to invalid `up_only` for MySQL

`oldie = 'true'` to `tinyint(1)` column is invalid value for MySQL:

```
Mysql2::Error: Incorrect integer value: 'true' for column 'oldie' at row 1: update horses set oldie = 'true'
```

activerecord/test/cases/invertible_migration_test.rb

@@ -163,11 +163,13 @@ def change
 
     class UpOnlyMigration < SilentMigration
       def change
-        add_column :horses, :oldie, :boolean, default: false
-        up_only { execute "update horses set oldie = 'true'" }
+        add_column :horses, :oldie, :integer, default: 0
+        up_only { execute "update horses set oldie = 1" }
       end
     end
 
+    self.use_transactional_tests = false
+
     setup do
       @verbose_was, ActiveRecord::Migration.verbose = ActiveRecord::Migration.verbose, false
     end
@@ -389,14 +391,14 @@ def test_migrate_revert_add_index_with_name
     def test_up_only
       InvertibleMigration.new.migrate(:up)
       horse1 = Horse.create
-      # populates existing horses with oldie=true but new ones have default false
+      # populates existing horses with oldie = 1 but new ones have default 0
       UpOnlyMigration.new.migrate(:up)
       Horse.reset_column_information
       horse1.reload
       horse2 = Horse.create
 
-      assert horse1.oldie? # created before migration
-      assert !horse2.oldie? # created after migration
+      assert 1, horse1.oldie # created before migration
+      assert 0, horse2.oldie # created after migration
 
       UpOnlyMigration.new.migrate(:down) # should be no error
       connection = ActiveRecord::Base.connection