An OpenACC async queue is always synchronized with itself, so invocations like
"#pragma acc wait(0) async(0)", or "acc_wait_async (0, 0)" don't make a lot of
sense, but are still valid.

	libgomp/
	PR libgomp/88495
	* plugin/plugin-nvptx.c (nvptx_wait_async): Don't refuse
	"identical parameters".
	* testsuite/libgomp.oacc-c-c++-common/asyncwait-nop-1.c: Update.
	* testsuite/libgomp.oacc-c-c++-common/lib-80.c: Remove.

From-SVN: r267152