[Clang][SME2] Add multi-vector add/sub builtins (#69725)

Adds the following SME2 builtins:
 - sv(add|sub)
 - sv(add|sub)_za32/za64,
 - sv(add|sub)_write_za32/za64

Other changes in this patch:
 - CGBuiltin.cpp: The GetAArch64SMEProcessedOperands function is created
    to avoid duplicating existing code from EmitAArch64SVEBuiltinExpr.
 - arm_sve.td: The add/sub SME2 builtins which do not operate on ZA have
been added to arm_sve.td, matching the corrosponding LLVM IR intrinsic
    names which start with @llvm.aarch64.sve for this reason.
- SveEmitter.cpp: Adds the createCoreHeaderIntrinsics function to remove
    duplicated code in createHeader & createSMEHeader. Uses a new enum
(ACLEKind) to choose either "__builtin_sme_" or "__builtin_sve_" when
    emitting the intrinsics.

See https://github.com/ARM-software/acle/pull/217/files