aco: use bit vectors for liveness sets

This seems to be much faster than hash sets. When compiling pipelines from
5 games, live_var_analysis takes about a third the time it used to and
fossilize-replay is ~1.77% faster.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Reviewed-by: Tony Wasserka <tony.wasserka@gmx.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6733>

src/amd/compiler/aco_validate.cpp

@@ -739,7 +739,8 @@ bool validate_ra(Program *program, const struct radv_nir_compiler_options *optio
       regs.fill(0);
 
       std::set<Temp> live;
-      live.insert(live_vars.live_out[block.index].begin(), live_vars.live_out[block.index].end());
+      for (unsigned id : live_vars.live_out[block.index])
+         live.insert(Temp(id, program->temp_rc[id]));
       /* remove killed p_phi sgpr operands */
       for (Temp tmp : phi_sgpr_ops[block.index])
          live.erase(tmp);