vdex: add checks in the event of file corruption.

It's unclear yet why the vdex files are being corrupted. But system
server, which is reading these vdex files should be robust to any vdex
corruption.

Bug: 199309980
Bug: 199395272
Test: test.py
Change-Id: Ia85ab8b23a0be4069cfa058a86fdf561f1ceb432
4 files changed