Validate incoming authority values.

A single provider may offer multiple authorities, so we now pass along
the authority being requested.  However, we need to validate that the
authority is actually serviced by the provider, similar to what we do
in validateIncomingUri().

Bug: 120673301
Test: atest android.content.cts
Test: atest android.provider.cts
Change-Id: Ia9734a42558ee9d46dc54f7e12b596cf03a520f5