[InstSimplify] Fold icmp of uadd.sat/usub.sat (PR63381)

Fold uadd.sat(X, Y) uge X and usub.sat(X, Y) ule X to true.

Proof: https://alive2.llvm.org/ce/z/596m9X

Fixes https://github.com/llvm/llvm-project/issues/63381.