Add distinct count incremental aggregator testcase to testng file.
<test name="siddhi-core-tests" enabled="true" preserve-order="true" parallel="false">
<classes>
<class name="org.wso2.siddhi.core.aggregation.AggregationTestCase"/>
+ <class name="org.wso2.siddhi.core.aggregation.DistinctCountAggregationTestCase"/>
<class name="org.wso2.siddhi.core.managment.AsyncTestCase"/>
<class name="org.wso2.siddhi.core.managment.EventTestCase"/>
