ProjectExplorer: Introduce RunWorker::reportDone()

To be used for short-lived tasks to signal that they are done.
Essentially an optional reportStarted() followed by reportStopped()

Using it in GdbServerPortsGatherer when the port list is ready fixes
the wrong "un-stopped" situation in RemoteLinux debugging when
the inferior finishes by itself.

Change-Id: I310831a7875fe6f2c598302b73cda6c9669efb1d
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/projectexplorer/runconfiguration.cpp

@@ -1586,6 +1586,33 @@ void RunWorker::reportStopped()
     emit stopped();
 }
 
+/*!
+ * This function can be called by a RunWorker implementation for short-lived
+ * tasks to notify its RunControl about this task being successful finished.
+ * Dependent startup tasks can proceed, in cases of spontaneous or scheduled
+ * stops, the effect is the same as \c reportStopped().
+ *
+ */
+void RunWorker::reportDone()
+{
+    switch (d->state) {
+        case RunWorkerState::Initialized:
+            QTC_CHECK(false);
+            d->state = RunWorkerState::Done;
+            break;
+        case RunWorkerState::Starting:
+            reportStarted();
+            reportStopped();
+            break;
+        case RunWorkerState::Running:
+        case RunWorkerState::Stopping:
+            reportStopped();
+            break;
+        case RunWorkerState::Done:
+            break;
+    }
+}
+
 /*!
  * This function can be called by a RunWorker implementation to
  * signal a problem in the operation in this worker. The