[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