[llvm][CodeGen] IR intrinsics for SVE2 contiguous conflict detection instructions.

Summary:
The IR intrinsics are mapped to the following SVE2 instructions:

* WHILERW <Pd>.<T>, <Xn>, <Xm>
* WHILEWR <Pd>.<T>, <Xn>, <Xm>

The intrinsics introduced in this patch are the IR counterpart of the
SVE ACLE functions `svwhilerw` and `svwhilewr` (all data type
variants).

Patch by Maciej Gąbka <maciej.gabka@arm.com>.

Reviewers: kmclaughlin, rengolin

Reviewed By: kmclaughlin

Subscribers: tschuett, kristof.beyls, hiraditya, danielkiss, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75862