fix potential "ressource deadlock avoided" system error

src/ApplicationModule.cc

@@ -92,7 +92,12 @@ namespace ChimeraTK {
         Application::getInstance().circularDependencyDetector.registerDependencyWait(variable);
         variable.getAppAccessorNoType().read();
         Application::getInstance().circularDependencyDetector.unregisterDependencyWait(variable);
-        Application::testableModeLock("Initial value read for poll-type " + variable.getName());
+        if(!Application::testableModeTestLock()) {
+          // The lock may have already been acquired if the above read() goes to a ConsumingFanOut, which sends out
+          // the data to a slave decorated by a TestableModeAccessorDecorator. Hence we heer must acquire the lock only
+          // if we do not have it.
+          Application::testableModeLock("Initial value read for poll-type " + variable.getName());
+        }
       }
     }
     for(auto& variable : getAccessorListRecursive()) {