use TRUE/FALSE.

	define rb_thread_sleep_deadly_allow_spurious_wakeup().

	* thread.c, thread_sync.c: define new function
	  rb_thread_sleep_deadly_allow_spurious_wakeup() and use it instead of
	  using sleep_forever() directly.

	allow Queue operation in trap.

	* thread_sync.c: allow spurious wakeup to check Queue status just after trap.
	  [Bug #12405]

	* test/thread/test_queue.rb: add a test for it.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@58036 b2dd03c8-39d4-4d8f-98ff-823fe69b080e