Add the new instruction formats.

This just adds new elements to the enum and adds code to InstrUtils
and dexdump which knows how to decode them.

In dexdump, I took advantage of the new index type table to simplify
how all the index-bearing instructions get dumped, to the point where
adding the new formats was really just a matter of picking the right
switch cases to add new labels to.

Change-Id: I9094b0d568e7c71ee237672bbea8c319274c6697