Add VelocityTraker Benchmark Tests

Tests added in this change are for AXIS_SCROLL only. We will need to
follow up with testing non-differential calculation (e.g. X/Y axes).

Bug: 268413323
Test: atest CorePerfTests:android.view.VelocityTrackerPerfTest
Change-Id: I050793d2408fcaa581973671fa8cb9f72678c7dc