[AArch64][SVE2] Add the SVE2.1 tbxq instruction

This patch adds the assembly/disassembly for the following instruction:

tbxq : Programmable table lookup within each quadword vector segment (merging)

The reference can be found here:
https://developer.arm.com/documentation/ddi0602/2022-09

Differential Revision: https://reviews.llvm.org/D137625