[InstCombine] Fold `(icmp eq/ne (xor x, y), C1)` even if multiuse

Two folds unlocked:
    `(icmp eq/ne (xor x, C0), C1)` -> `(icmp eq/ne x, C2)`
    `(icmp eq/ne (xor x, y), 0)` -> `(icmp eq/ne x, y)`

This fixes regressions assosiated with #87180

Closes #87275