[AArch64][SelectionDAG] Mask for SUBS with multiple users cannot be elided (#90911)

In DAGCombiner, the `performCONDCombine` function attempts to remove AND
instructions in front of SUBS (cmp) instructions for which the AND is
transparent. The rules for that are correct, but it fails to take into
account the case where the SUBS instruction has multiple users with
different condition codes for comparison and simply removes the AND for
all of them. This causes a miscompilation in the attached test case.