Add maxTargetSdk restriction to unused APIs.

These are APIs that have @UnsupportedAppUsage but for which we don't
have any evidence of them currently being used, so should be safe to
remove from the unsupported list.

Bug: 170729553
Test: Treehugger
Merged-In: I881fc8c5e5ef9d055dfc43f7bde99faaaf313109
Change-Id: Iffbdac31041c43367c302f01e8e78cd9b7fb1f2d