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
Change-Id: I4c8fd0006f950de9955242e93968fb0996ceb372
642 files changed