DO NOT MERGE: ApfTest: tag tests with @SmallTest or @MediumTest

Test methods not tagged with @{Small,Medium,Large}Test will not appear
in the Android Platform Continuous Testing dashboard.

Test methods tagged with @LargeTest will not be run in the Android
Platform Continuous Testing dashboard.

Test: ApfTest passes ($runtest frameworks-net)
Bug: 31479480

(cherry picked from commit 4195c283)

Change-Id: Ia215fc8e2ccc61f6223c24fdf390e1e759de302f