OpenMP, GCN: Add interop-hsa testcase

This testcase ensures that the interop HSA support is sufficient to run
a kernel manually on the same device.

libgomp/ChangeLog:

	* testsuite/libgomp.c/interop-hsa.c: New test.

(cherry picked from commit 8d84ea28510054fbbb8a2b7441916bd75e29163f)