Add async version of "uncanonicalize"

This CL is basically identical to http://ag/10353234, which
did the same with the sister method, "canonicalize".

Fixes: b/147705670
Test: atest FrameworksCoreTests:android.content.ContentResolverTest
Change-Id: Ide93850f225cdd61779a62fc2c4666efe438b536
9 files changed