Remove test parallelism from ant build.xml
Remove test parallelism from ant build.xml

 patch by Mick Semb Wever; reviewed by Berenguer Blasi, Yifan Cai for CASSANDRA-16595

michaelsembwever/cassandra,tjake/cassandra,szhou1234/cassandra,belliottsmith/cassandra,belliottsmith/cassandra,adelapena/cassandra,instaclustr/cassandra,michaelsembwever/cassandra,adelapena/cassandra,pauloricardomg/cassandra,thelastpickle/cassandra,driftx/cassandra,driftx/cassandra,thelastpickle/cassandra,blambov/cassandra,apache/cassandra,adelapena/cassandra,scylladb/scylla-tools-java,adelapena/cassandra,pauloricardomg/cassandra,scylladb/scylla-tools-java,mshuler/cassandra,blambov/cassandra,jrwest/cassandra,mike-tr-adamson/cassandra,michaelsembwever/cassandra,tjake/cassandra,szhou1234/cassandra,jrwest/cassandra,blambov/cassandra,thelastpickle/cassandra,pauloricardomg/cassandra,pauloricardomg/cassandra,tjake/cassandra,driftx/cassandra,apache/cassandra,tjake/cassandra,belliottsmith/cassandra,belliottsmith/cassandra,mike-tr-adamson/cassandra,mshuler/cassandra,instaclustr/cassandra,apache/cassandra,instaclustr/cassandra,jrwest/cassandra,mshuler/cassandra,instaclustr/cassandra,mike-tr-adamson/cassandra,michaelsembwever/cassandra,szhou1234/cassandra,mike-tr-adamson/cassandra,blambov/cassandra,thelastpickle/cassandra,scylladb/scylla-tools-java,driftx/cassandra,jrwest/cassandra,szhou1234/cassandra,apache/cassandra,mshuler/cassandra,scylladb/scylla-tools-java