[hotfix] Clear interrupted flag in stream task cancellation

We clear the interrupted flag before the cleanup code block of task cancellation.
Otherwise, code that would like to wait until services are properly shutdown will
always immediately return from calls that are supposed to be blocking waits.

flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/tasks/StreamTask.java

@@ -348,6 +348,9 @@ public final void invoke() throws Exception {
 			// clean up everything we initialized
 			isRunning = false;
 
+			// clear the interrupted status so that we can wait for the following resource shutdowns to complete
+			Thread.interrupted();
+
 			// stop all timers and threads
 			if (timerService != null && !timerService.isTerminated()) {
 				try {