GCN, nvptx offloading: Restrain 'WARNING: program timed out.' while in 'dynamic_cast'" [PR119692]

	PR target/119692
	libgomp/
	* testsuite/libgomp.c++/pr119692-1-4.C: '{ dg-timeout 10 }'.
	* testsuite/libgomp.c++/pr119692-1-5.C: Likewise.
	* testsuite/libgomp.c++/target-exceptions-bad_cast-1.C: Likewise.
	* testsuite/libgomp.c++/target-exceptions-bad_cast-2.C: Likewise.
	* testsuite/libgomp.oacc-c++/exceptions-bad_cast-1.C: Likewise.
	* testsuite/libgomp.oacc-c++/exceptions-bad_cast-2.C: Likewise.

(cherry picked from commit b5f48e7872db30b8f174cb2c497868a358bf75d6)