Make swc1 and lwc1 faster even without fastmem

This just adds the floats in basically the same way.

Maybe there's a better way, but I used a static temporary `ssLoadStoreTemp` as a memory intermediary for the FPU.  It's only used during the slow paths (which the games I tested never hit, I had to kill the jumps to test them), so shouldn't be a huge deal.

This also has some benefit when fastmem is on, as it special cases static addresses, which seem to be used often enough.

-[Unknown]