[ARM][MVE][Intrinsics] Add VQADDQ, VHADDQ, VRHADDQ, VQSUBQ, VHSUBQ, VQDMULHQ, VQRDMULHQ intrinsics.

Summary: Add VQADDQ, VHADDQ, VRHADDQ, VQSUBQ, VHSUBQ, VQDMULHQ, VQRDMULHQ intrinsics and unit tests.

Reviewers: simon_tatham, ostannard, dmgreen, miyuki

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

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D71198