Call Thread::stopThread() in NamedPipeThread's destructor to fix an assertion when running the NamedPipe unit tests

modules/juce_core/network/juce_NamedPipe.cpp

@@ -207,6 +207,11 @@ private:
                 pipe.openExisting (pipeName);
         }
 
+        ~NamedPipeThread()
+        {
+            stopThread (100);
+        }
+
         NamedPipe pipe;
         const String& pipeName;
         WaitableEvent& workCompleted;