IBM Z: Provide rawmemchr{qi,hi,si} expander

IBM Z: Provide rawmemchr{qi,hi,si} expander

gcc/ChangeLog:

	* config/s390/s390-protos.h (s390_rawmemchr): Add prototype.
	* config/s390/s390.c (s390_rawmemchr): New function.
	* config/s390/s390.md (rawmemchr<SINT:mode>): New expander.
	* config/s390/vector.md (@vec_vfees<mode>): Basically a copy of
	the pattern vfees<mode> from vx-builtins.md.
	* config/s390/vx-builtins.md (*vfees<mode>): Remove.

gcc/testsuite/ChangeLog:

	* gcc.target/s390/rawmemchr-1.c: New test.