[InstCombine] try to narrow more shifted bswap-of-zext

Try to narrow more bswap, if the shift amount is less than the zext
(bswap (zext X)) >> C --> (zext (bswap X)) << C'

https://alive2.llvm.org/ce/z/i7ddjn

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D124598