Use shared namespaces for bundled apps

Shared namespaces clone the list of loaded native
libraries from the caller namespace. This allows
classloaders for bundled apps to share already loaded
libraries with default namespace.

Bug: http://b/26165097
Bug: http://b/22548808
Change-Id: Ia90b603a0ca97194618b82fb191d6790a4b1f281
(cherry picked from commit 986f650d)