Fold: (setcc (shr X, ShAmt), CI), where 'cc' is eq or ne. This xform

Fold: (setcc (shr X, ShAmt), CI), where 'cc' is eq or ne.  This xform
triggers often, for example:

6x in povray, 1x in gzip, 279x in gcc, 1x in crafty, 8x in eon, 11x in perlbmk,
362x in gap, 4x in vortex, 14 in m88ksim, 211x in 126.gcc, 1x in compress,
11x in ijpeg, and 4x in 147.vortex.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16521 91177308-0d34-0410-b5e6-96231b3b80d8