[GlobalISel][KnownBits] Early return on out of bound shift amounts

If the known shift amount is bigger than or equal to the bitwidth of the type of the value to be shifted,
the result is target dependent, so don't try to infer any bits.

This fixes a crash we've seen in one of our internal test suites.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D89232