middle-end/113576 - zero padding of vector bools when expanding compares

middle-end/113576 - zero padding of vector bools when expanding compares

The following zeros paddings of vector bools when expanding compares
and the mode used for the compare is an integer mode.  In that case
targets cannot distinguish between a 4 element and 8 element vector
compare (both get to the QImode compare optab) so we have to do the
job in the middle-end.

	PR middle-end/113576
	* expr.cc (do_store_flag): For vector bool compares of vectors
	with padding zero that.
	* dojump.cc (do_compare_and_jump): Likewise.