[InstSimplify] Protect against more poison in SimplifyWithOpReplaced (PR47322)
Replace the check for poison-producing instructions in
SimplifyWithOpReplaced() with the generic helper canCreatePoison()
that properly handles poisonous shifts and thus avoids the problem
This additionally fixes a bug in IIQ.UseInstrInfo=false mode, which
previously could have caused this code to ignore poison flags.
Setting UseInstrInfo=false should reduce the possible optimizations,
not increase them.
This is not a full solution to the problem, as poison could be
introduced more indirectly. This is just a minimal, easy to backport
Differential Revision: https://reviews.llvm.org/D86834