Undo dex2dex compilation before invoking LoadHook

We need to undo any dex_to_dex compilation that might have taken place
before passing a dex file to any registered ClassFileLoadHooks to
ensure that no internal opcodes are present in any methods.

Test: ./test.py --host -j40
Bug: 36653594

Change-Id: Ia42c77312e685d69f6b3ea764fad01710b10ab45