[AArch64][SVE2] Add the SVE2.1 contiguous stores to multiple consecutive vectors

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

st1*   : Contiguous store of bytes to multiple consecutive vectors -
 (scalar + scalar) and (scalar + immediate)
stnt1* : Contiguous store non-temporal of bytes to multiple consecutive
 vectors - (scalar + scalar) and (scalar + immediate)

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

Differential Revision: https://reviews.llvm.org/D136686