Remove unused Debug Switches

oap-server/server-receiver-plugin/skywalking-trace-receiver-plugin/src/main/java/org/apache/skywalking/oap/server/receiver/trace/provider/handler/v6/grpc/TraceSegmentReportServiceHandler.java

@@ -33,11 +33,9 @@ public class TraceSegmentReportServiceHandler extends TraceSegmentReportServiceG
 
     private static final Logger logger = LoggerFactory.getLogger(TraceSegmentServiceHandler.class);
 
-    private final Boolean debug;
     private final SegmentParseV2.Producer segmentProducer;
 
     public TraceSegmentReportServiceHandler(SegmentParseV2.Producer segmentProducer) {
-        this.debug = System.getProperty("debug") != null;
         this.segmentProducer = segmentProducer;
     }