s390: arch15: Vector maximum/minimum: Add 128-bit integer support

For previous architectures emulate operation max/min.

gcc/ChangeLog:

	* config/s390/s390-builtins.def: Add 128-bit variants and remove
	bool variants.
	* config/s390/s390-builtin-types.def: Update accordinly.
	* config/s390/s390.md: Emulate min/max for GPR.
	* config/s390/vector.md: Add min/max patterns and emulate in
	case of no VXE3.

gcc/testsuite/ChangeLog:

	* gcc.target/s390/vector/vec-max-emu.c: New test.
	* gcc.target/s390/vector/vec-min-emu.c: New test.