Avoid clearing some caches on save/load state

This should make loading and saving states faster.  A downside is that previously, saving state would clear the jit cache (possibly working around jit bugs), which it no longer does.

It will also require save/load state to clear FBO/texture caches (which I realize some people savestate to workaround texture cache issues.)  Loading state has that effect, still.

This also means saving state won't cause the display to blink.

With these changes, a "rewind" feature based on savestates becomes mostly possible.  I can only see it being practical on desktop, however, mostly due to memory requirements (and Snappy seems still too slow to run against such large data constantly.)

-[Unknown]