i965/fs: Ignore actual latency pre-reg-alloc.

i965/fs: Ignore actual latency pre-reg-alloc.

We care about depth-until-program-end, as a proxy for "make sure I
schedule those early instructions that open up the other things that can
make progress while keeping register pressure low", not actual latency
(since we're relying on the post-register-alloc scheduling to actually
schedule for the hardware).

total instructions in shared programs: 1609931 -> 1609931 (0.00%)
instructions in affected programs:     0 -> 0
GAINED:                                55
LOST:                                  43

Cc: "10.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>