Start using shared libraries class loader.

Change 1/2. Change 2/2 will setup the class loader namespace for
shared libraries.

This change sets up shared libraries class loaders for applications
and for dexopt.

bug: 111174995
Test: DexoptUtilsTest, device boots
Exempt-From-Owner-Approval: PS1 was approved by owner, PS2 is a build fix.

(cherry picked from commit 8d144eb8)
Merged-In: Ie9a2b4eaa85cda59951703433f7a2d03bc12095d

Change-Id: I76383308418485ad6739f8a404d02c2771e4afe4