[x86] Clean up the shift lowering vector shuffle tests a bit using my
script. Notably this folds all the SSE cases together into a single
FileCheck block. It also adds a vex prefix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223610 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Cleanup the combining vector shuffle tests a bit by merging
identical checks for different SSE variants into a single block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223611 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Switch a constant selection test to use positive assertions and to
store to real pointers so that its clear that the right code is in fact
being generated.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223612 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Clean up the SSE1 test to use a slightly different pattern for
matching offsets. I don't expect this to really matter, but its what the
latest incarnation of my script for maintaining these tests happens to
produce, and so its simpler for me if everything matches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223613 91177308-0d34-0410-b5e6-96231b3b80d8