Fix 'libgomp.fortran/target-print-1.f90', 'libgomp.oacc-fortran/print-1.f90' for offload target nvptx

	libgomp/
	* testsuite/lib/libgomp.exp
	(check_effective_target_offload_target_nvptx): New proc.
	* testsuite/libgomp.fortran/target-print-1.f90: Use it with
	'dg-skip-if'.
	* testsuite/libgomp.oacc-fortran/print-1.f90: Likewise.
	* testsuite/libgomp.fortran/target-print-1-nvptx.f90: New file.
	* testsuite/libgomp.oacc-fortran/print-1-nvptx.f90: Likewise.

From-SVN: r278779