Add 'require' for Hash#with_indifferent_access

ActiveJob::Arguments uses Hash#with_indifferent_access.
But, activejob gem does not require Hash extension library.
When we use activejob as standalone,
we need extra require statement. This is unhandy.

This commit fixes it.
Merge pull request #18119 from joker1007/add_require_core_ext_hash_to_activejob

Add 'require' for Hash#with_indifferent_access to active_job/arguments.rb