Add missing tests for filtering routes

To test package orders, host side tests are added.
AllowedPackages istested as well.

Additionaly, RouteDiscoveryRequest#getRequiredFeatures is removed
as it doesn't seem to be necessary.

Adding tests, some bugs are found and fixed.

Test: atest MediaRouter2HostTest android.media.cts.MediaRouter2Test
MediaRouter2ManagerTest
Bug: 193631822

Change-Id: I315d6e0d648777566404875e300030740a482c81