[x86] adjust select to sra tests; NFC
[x86] adjust select to sra tests; NFC

Avoid demanded-bits-based specializations (that may not be ideal,
but that's another problem).

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@374783 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm