Remove explicit "with default proc" tests. Run the majority of tests with/without default procs.
Remove explicit "with default proc" tests. Run the majority of tests with/without default procs.

ruby-concurrency/thread_safe,rranelli/thread_safe,ruby-concurrency/thread_safe,ruby-concurrency/thread_safe,headius/thread_safe,rranelli/thread_safe,headius/thread_safe,rranelli/thread_safe