Revert "OtaDexopt: Temporarily disable"

This reverts commit c0ba0e4b.

The underlying issue ('&' as shared library path for system apps) is
fixed and the backwards-compat path (versioning of the protocol) is
merged (commit e164b18c2097c4bd40da0cf559b0339d697896ef).

Bug: 115997390
Change-Id: I235f3f9137daf7d4be502b385783e0dffe2fce62
Test: m
Test: OTA tests
Test: manual OTA