Remove no-op code, protect global space from test code

[stevenjonescgm]

I'm working on a different PR (that's potentially contentious) and found some accidentally-working code.

Maybe middleware/sever/unique_jobs.rb#call was intended to release the lock if

1. an exception was raised
2. before_yield? was true but redis failed to delete the key.

However,

(unlocked != 1) will always be true because (without exceptions) unlocked will either be integer 0 or string "1" or maybe string "\"1\"" because of the call to .inspect()

This code happened to to leave the lock in place if option['unique_unlock_order'] == :never because !defined? unlocked || unlocked != 1 is the same as !defined?(unlocked || unlocked != 1) not !defined?(unlocked) || (unlocked != 1)

I spent some time thinking about how to write a test case to demonstrate, but I think that may not be possible since even if I stub one of the methods before the unlocked assignment to raise, unlocked is still a defined local_variable.

If the design was to unlock on exception, then that logic ought to go into after_yield? with a side-effect from unlock(payload_hash) and maybe add a never_unlock? or always_unlock? method.

as for unique_jobs_spec.rb, "when get_sidekiq_options[:unique_unlock_order] is nil" has an order-dependency on being run before any .sidekiq_options unique_unlock_order: :before_yield etc so I made the tests clone UniqueWorker before modifying class_variables