aco: implement 64-bit sgpr swaps

aco: implement 64-bit sgpr swaps

In our pipeline-db, helps almost exclusively Detroit: Become Human.

Totals from 6726 (5.36% of 125503) affected shaders:
CodeSize: 74680952 -> 74102228 (-0.77%)
Instrs: 14551507 -> 14406001 (-1.00%)
Cycles: 1748272436 -> 1690173104 (-3.32%)
VMEM: 964671 -> 964058 (-0.06%)
Copies: 1993312 -> 1847806 (-7.30%)

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4469>