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: I626caf7c1fe46c5ab1f39c2895b42a34319f771a
Change-Id: I54e5ecd11e76ca1de3c5893e3a98b0108e735413