[AArch64] Use `umin` for `x != 0` when `+cssc` is enabled

[Kmeakin]

https://godbolt.org/z/Mdr63hKcT

auto src(unsigned long x0) { return x0 != 0; }
auto tgt(unsigned long x0) { asm("umin x0, x0, #1"); }

src(unsigned long):
        cmp     x0, #0
        cset    w0, ne
        ret

tgt(unsigned long):
        umin    x0, x0, #1
        ret

[llvmbot]

@llvm/issue-subscribers-backend-aarch64

Author: Karl Meakin (Kmeakin)

https://godbolt.org/z/78zeM8a7z ```c++ auto src(unsigned long x0) { return x0 != 0; } auto tgt(unsigned long x0) { asm("umin x0, x0, #1"); } ```

src(unsigned long):
        cmp     x0, #<!-- -->0
        cset    w0, ne
        ret

tgt(unsigned long):
        umin    x0, x0, #<!-- -->1
        ret