Ensure globals reset after Active Storage tests

This ensures `ActiveRecord::Base.strict_loading_by_default` and
`ActiveStorage.track_variants` are reset to their original values even
when an error (e.g. an assertion failure) is raised inside
`with_strict_loading_by_default` and `without_variant_tracking` blocks.

activestorage/test/test_helper.rb

@@ -105,13 +105,15 @@ def with_strict_loading_by_default(&block)
       strict_loading_was = ActiveRecord::Base.strict_loading_by_default
       ActiveRecord::Base.strict_loading_by_default = true
       yield
+    ensure
       ActiveRecord::Base.strict_loading_by_default = strict_loading_was
     end
 
     def without_variant_tracking(&block)
       variant_tracking_was = ActiveStorage.track_variants
       ActiveStorage.track_variants = false
       yield
+    ensure
       ActiveStorage.track_variants = variant_tracking_was
     end