Android: delete androidContentFileEngineHandler in terminateQt()

Similar to other Android file engine handlers.

Change-Id: I63591e09312e439eee1e7bdd71a65d3df4cefbae
Reviewed-by: Petri Virkkunen <petri.virkkunen@qt.io>
(cherry picked from commit cd5d30fa3368ab9cf995ed934ea737f3e569e9ce)

src/plugins/platforms/android/androidjnimain.cpp

@@ -533,6 +533,8 @@ static void terminateQt(JNIEnv *env, jclass /*clazz*/)
     m_androidPlatformIntegration = nullptr;
     delete m_androidAssetsFileEngineHandler;
     m_androidAssetsFileEngineHandler = nullptr;
+    delete m_androidContentFileEngineHandler;
+    m_androidContentFileEngineHandler = nullptr;
     delete m_backendRegister;
     m_backendRegister = nullptr;
     sem_post(&m_exitSemaphore);