[ScalarEvolution] Add bailout to avoid zext of pointer.

The RHS of an isImpliedCond call can be a pointer even if the LHS is
not. This is similar to bfa2a81e.

Not going to include a testcase; an IR testcase would be extremely
complicated and fragile.

Fixes https://github.com/llvm/llvm-project/issues/51936 .

Differential Revision: https://reviews.llvm.org/D114555