Clean up after newlib "nvptx: In offloading execution, map '_exit' to 'abort' [GCC PR85463]"

	PR target/85463
	libgfortran/
	* runtime/minimal.c [__nvptx__] (exit): Don't override.
	libgomp/
	* config/nvptx/error.c (exit): Don't override.
	* testsuite/libgomp.oacc-fortran/error_stop-1.f: Update.
	* testsuite/libgomp.oacc-fortran/error_stop-2.f: Likewise.
	* testsuite/libgomp.oacc-fortran/error_stop-3.f: Likewise.
	* testsuite/libgomp.oacc-fortran/stop-1.f: Likewise.
	* testsuite/libgomp.oacc-fortran/stop-2.f: Likewise.
	* testsuite/libgomp.oacc-fortran/stop-3.f: Likewise.