Add CTS test for StateTracker annotations

Test using a metric which slices by BleScanStateChanged atom and uses a
fake atom as the what for the metric.

Bug: 153880954
Test: atest
CtsStatsdHostTestCases: android.cts.statsd.metric.CountMetricsTests#testSlicedStateCountMetric
Change-Id: I27f561f83bbb638c065e059f677a76fc40f0e3a9
2 files changed