Reorder VFPU registers in memory so that we can flush and reload them in bulk more often.

Doesn't actually do that yet, that's for the NEON branch.
Reorder vfpu data in saved kernel contexts when loading in a new version.
Extend sanity check for vfpu reordering array.
Merge pull request #4656 from hrydgard/vfpu-reg-order

Reorder VFPU registers in memory so that we can flush and reload them with vector moves.