Eat some cycles in a few minor places

I originally did this quite some time ago to try to improve perf/stutter in some game (these were basically the only funcs it was calling in its main loop.)

It didn't end up helping that much, but I found a few games that were improved by sceKernelCheckCallback() eating cycles.  Since I already measured these funcs, we might as well eat cycles in them.  May improve performance and stutter, if only slightly, in several games where these funcs are used in loops.

-[Unknown]