optabs.c (expand_atomic_test_and_set): Honor atomic_test_and_set_trueval even when atomic_test_and_set optab is not in use.

	* optabs.c (expand_atomic_test_and_set): Honor
	atomic_test_and_set_trueval even when atomic_test_and_set
	optab is not in use.

From-SVN: r184862