Add pr85381*.c test-cases that are already passing without the fix for PR85381.

Build and reg-tested on x86_64 with nvptx accelerator.

2018-12-19  Tom de Vries  <tdevries@suse.de>

	* testsuite/libgomp.oacc-c-c++-common/pr85381-2.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/pr85381-3.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/pr85381-4.c: New test.

From-SVN: r267268