[game] dropping frames while loading

[water111]

I measured, and it looks like we have 3 frames that likely skip when loading:

stage tfrag took 12.32 ms
Loader::update slow setup: 12.3ms

stage tfrag took 10.25 ms
Loader::update slow setup: 10.3ms

stage collide took 12.03 ms
stage merc took 11.31 ms
Loader::update slow setup: 24.8ms