[Bug target/115974] sat_add, etc. vector patterns not done for aarch64 (non-sve)

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115974

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
here is testcase for ustrunc at least (note llvm does not use uqxtn here even
though it could):
```
void ustrunc0(unsigned long long *__restrict__  a, unsigned * __restrict__ b)
{
        int i = 0;
        for(int i = 0;i < 1024;i ++)
        {
          unsigned long long tt = a[i];
          if (tt > -1u)
            tt = -1u;
          b[i] = tt;
       }
}
```