[AArch64] Implement reinterpret builtins for SVE vector tuples (#69598)

This patch adds reinterpret builtins as proposed here:
ARM-software/acle#275.

The builtins take the form:

    sv<dst>x<N>_t svreinterpret_<dst>_<src>_x<N>(sv<src>x<N>_t op)

where
- <src> and <dst> designate the source and the destination type,
respectively, all pairs chosen from {s8, u8, s16, u8, s32, u32, s64,
u64, bf16, f16, f32, f64}
  - <N> designated the number of tuple elements, 2, 3 or 4

A short (overloaded) for is also provided, where the destination type is
explicitly designated and the source type is deduced from the parameter
type. These take the form

    sv<dst>x<N>_t svreinterpret_<dst>(sv<src>x<N>_t op)

For example:

    svuin16x2_t svreinterpret_u16_s32_x2(svint32x2_t op);
    svuin16x2_t svreinterpret_u16(svint32x2_t op);

clang/lib/CodeGen/CGBuiltin.cpp

@@ -9994,7 +9994,7 @@ Value *CodeGenFunction::EmitAArch64SVEBuiltinExpr(unsigned BuiltinID,
                                                   const CallExpr *E) {
   llvm::Type *Ty = ConvertType(E->getType());
   if (BuiltinID >= SVE::BI__builtin_sve_reinterpret_s8_s8 &&
-      BuiltinID <= SVE::BI__builtin_sve_reinterpret_f64_f64) {
+      BuiltinID <= SVE::BI__builtin_sve_reinterpret_f64_f64_x4) {
     Value *Val = EmitScalarExpr(E->getArg(0));
     return EmitSVEReinterpret(Val, Ty);
   }