[ARM,MVE] Add vbrsrq intrinsics family

Summary:
This patch adds a new MVE intrinsics family, `vbrsrq`: vector bit
reverse and shift right. The intrinsics are compiled into the VBRSR
instruction. Two new LLVM IR intrinsics were also added: arm.mve.vbrsr
and arm.mve.vbrsr.predicated.

Reviewers: simon_tatham, dmgreen, ostannard, MarkMurrayARM

Reviewed By: simon_tatham

Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D74721