intel/fs: Faster lookup for acp entries during copy propagation

Create map of reg_space result to set of acp entries to avoid traversing
whole acp table. This can be done because regions_overlap function requires
reg_space match (at least for VGRF and FIXED_GRF registers).

shader-db:

total instructions in shared programs: 1104355 -> 1104355 (0.00%)
instructions in affected programs: 0 -> 0
helped: 0
HURT: 0

total loops in shared programs: 1295 -> 1295 (0.00%)
loops in affected programs: 0 -> 0
helped: 0
HURT: 0

total cycles in shared programs: 189266218 -> 189266218 (0.00%)
cycles in affected programs: 0 -> 0
helped: 0
HURT: 0

total spills in shared programs: 1893 -> 1893 (0.00%)
spills in affected programs: 0 -> 0
helped: 0
HURT: 0

total fills in shared programs: 2433 -> 2433 (0.00%)
fills in affected programs: 0 -> 0
helped: 0
HURT: 0

total sends in shared programs: 58986 -> 58986 (0.00%)
sends in affected programs: 0 -> 0
helped: 0
HURT: 0

LOST:   0
GAINED: 0

Total CPU time (seconds): 46.18 -> 43.60 (-5.59%)

Signed-off-by: Kostiantyn Lazukin <kostiantyn.lazukin@globallogic.com>