Plumb split APKs into public API.

Introduces new ApplicationInfo fields to surface zero or more split
APKs for an application.  Splice these APKs into both the class
loader and resource system.  Cleaner building of these paths.

Run dexopt() on all split APKs found after a parse, and populate
into ApplicationInfo.

Change-Id: I4a376bf4492d84ea95aafa866e106ea43a43e492