Prepare to move dexopt calls to Binder.

Since InstallerConnection is about to be replaced by a new installd
Binder interface, this change moves OtaDexoptService to override and
manually cook up the 'dexopt' command line that it expects to collect
from PackageDexOptimizer.

Since OtaDexoptService is designed to be run in isolation, add a new
mode to Installer which ignores calls that aren't being intercepted.

Also moves to a single dexopt() method instead of having overloads.

Test: builds, boots, fake OTA works
Bug: 13758960, 30944031
Change-Id: I3a6a115289f1542d6df3e2993b9720118b7d1e8d