First CL at ag/10697747. Sending ValueMetricProducer_test as multiple CLs to retain diff and make
it easier to review.
Updates from TestPushedEventsWithoutCondition to TestSkipZeroDiffOutputMultiValue
Test: bit statsd_test:*
Bug: 149590301
Change-Id: Ie429f36124d475c16652eb52fed41ab88128ffdd