[AMDGPU] Add constrained shift pattern matches.

The motivation for this is due to clang's conformance to
https://www.khronos.org/registry/OpenCL/specs/3.0-unified/html/OpenCL_C.html#operators-shift
which makes clang emit (<shift> a, (and b, <width> - 1)) for `a <shift> b`
in OpenCL where a is an int of bit width <width>.

Differential revision: https://reviews.llvm.org/D110231