Added new -v option to dexlayout to verify output dex file.

Passing -v will cause dexlayout to do an IR level comparison of the
output with the original input dex file. This checks that the data in
the dex files are the same, but allows for different offsets since the
output dex file may have a different layout.

Test: mm test-art-host
Bug: 36107940
Change-Id: If75a93973ffdd2d91111727f089713c800d8cee8