[AArch64] Extend SBC combine to handle CSET HI (#192708)
The `performSubWithBorrowCombine` previously only matched `CSET LO`
(unsigned <).
This extends it to also handle `CSET HI` (unsigned >) by swapping the
`SUBS` operands, since `a > b` is equivalent to `b < a`.
This resolves the FIXME left in the test from #165271.
