[InstCombine] Fold zext-of-icmp with no shift (#68503)

This regression triggers after commit f400daae to fix infinite loop
issue.

In this case, we can known the shift count is 0, so it will not be
triggered by the form of (iN (~X) u>> (N - 1)) in commit 21d3871b, of
which N indicates the data type bitwidth of X.

Fixes https://github.com/llvm/llvm-project/issues/68465.