DEV: Don't user before(:all)/after(:all) (#13389)

Leaking state and non-obvious order (before :all runs *before* RailsHelper.test_setup) are not worth it.
A replacement PR for #13370. Fixes some flaky specs, e.g.
```
bin/rspec './spec/components/freedom_patches/translate_accelerator_spec.rb[1:3]' './spec/jobs/clean_up_user_export_topics_spec.rb[1:1]' --tag ~type:multisite --seed 35994
```

Also included:
* DEV: No need for locale reset (we do it anyway in rails_helper in `test_setup`)

spec/components/freedom_patches/translate_accelerator_spec.rb

@@ -3,18 +3,14 @@
 require "rails_helper"
 
 describe "translate accelerator" do
-  before(:all) do
+  before do
     @original_i18n_load_path = I18n.load_path.dup
     I18n.load_path += Dir["#{Rails.root}/spec/fixtures/i18n/translate_accelerator.*.yml"]
     I18n.reload!
   end
 
-  after(:all) do
-    I18n.load_path = @original_i18n_load_path
-    I18n.reload!
-  end
-
   after do
+    I18n.load_path = @original_i18n_load_path
     I18n.reload!
   end