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: Ida716516dd82c00ceb446b1af07a77b1af36b66c
4 files changed