[AArch64] Fix crash with empty/pseudo-only blocks in A53 erratum (835769) workaround

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219684 91177308-0d34-0410-b5e6-96231b3b80d8
[AVX512] Extended avx512_binop_rm to BW/VL subsets.
Added encoding tests.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219685 91177308-0d34-0410-b5e6-96231b3b80d8