Check if host supports multi-byte NOPs before enabling CET on host.

gcc/

	PR bootstrap/99703
	* configure: Regenerated.

libbacktrace/

	PR bootstrap/99703
	* configure: Regenerated.

libcc1/

	PR bootstrap/99703
	* configure: Regenerated.

libcpp/

	PR bootstrap/99703
	* configure: Regenerated.

libdecnumber/

	PR bootstrap/99703
	* configure: Regenerated.

lto-plugin/

	PR bootstrap/99703
	* configure: Regenerated.