Request#check_method no longer breaks when :en is not available locale

Request#check_method would use to_sentence(locale: :en), which breaks when
I18n.available_locales does not include :en and
I18n.enforce_available_locales is true (default).

Inlined to_sentence functionality to solve this.
Merge pull request #17221 from StefanH/fix-unknown-http-method-message

Invalid HTTP method will raise I18n::InvalidLocale if :en is not a valid locale.
ActiveJob: allow blank queue names

As discussed in #17195, Que uses blank queue names by default for
performance reasons. At the very least, ActiveJob should allow users to
choose "" as their queue name. This commit allows blank queue names, as
well as tests to make sure that nil queue names still use the default.
Merge pull request #17223 from bgentry/active-job-empty-queue-name

ActiveJob: allow empty queue names
tests, move `original_` var assignments outside of `begin`.