fold-vec-abs-short-fwrap.c: Add xxspltib to scan-asembler valid instructions list.

fold-vec-abs-short-fwrap.c: Add xxspltib to scan-asembler valid instructions list.

[testsuite]

	2018-01-19  Will Schmidt <will_schmidt@vnet.ibm.com>

	* gcc.target/powerpc/fold-vec-abs-short-fwrap.c: Add xxspltib to
	scan-asembler valid instructions list.
	* gcc.target/powerpc/fold-vec-abs-short.c: Same.
	* gcc.target/powerpc/fold-vec-shift-left-longlong.c: Clean up
	power8-vector requirement and option.
	* gcc.target/powerpc/fold-vec-shift-left-fwrapv.c: Same.

From-SVN: r256947