[AArch64][SME2] Add multi-vector min/max intrinsics

Adds intrinsics for the following SME2 instructions:
 - smax, umax, fmax (single, 2 & 4 vector)
 - smax, umax, fmax (multi, 2 & 4 vector)
 - smin, umin, fmin (single, 2 & 4 vector)
 - smin, umin, fmin (multi, 2 & 4 vector)

NOTE: These intrinsics are still in development and are subject to future changes.

Reviewed By: david-arm

Differential Revision: https://reviews.llvm.org/D142485