AVX-512 set: Added BROADCAST instructions
with lowering logic and a test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187884 91177308-0d34-0410-b5e6-96231b3b80d8
Lit: Resurrect --no-execute dropped in r187852.

For now, builders in bb.pgr.jp are using it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187886 91177308-0d34-0410-b5e6-96231b3b80d8