s390: arch15: New instruction variants supporting 128-bit integer

Add new instruction variants and also extend builtins in order to deal
with 128-bit integer.

gcc/ChangeLog:

	* config/s390/s390-builtins.def: Add new instruction variants.
	* config/s390/s390-builtin-types.def: Update accordingly.
	* config/s390/vecintrin.h: Add new defines.
	* config/s390/vector.md: Adapt insns for new instruction
	variants.
	* config/s390/vx-builtins.md: Ditto.