Revert "OatFileAssistant: look at vdex file for IsDexOptNeeded"

This reverts commit 402089a27b25a9d1112c49189eb83a567719188f.

Leads to crashes when vdex doesn't seem to contain dex files.

Bug: 34339100
Bug: 34685231
Change-Id: I57c3134892a190f792e196e6d7162285e74a64e4
Test: m test-art-host
3 files changed