Set the correct class loader in Resources

The class loader in Resources is now used to inflate drawables. Because
layoutlib was using the system class loader, the drawables would fail to
inflate.
With this change, Resources will use the layoutlib class loader instead
of the system one.

Test: Tested from the studio side
Change-Id: I933ff68e704f9d3599b69cd74e98e44bdca3c789