Ensure QAndroidJniObjects from implicit conversion outlive the JNI call
When passing in complex types that we can implicitly convert we went directly to the jobject handle via a temporary QAndroidJniObject so far, which at the point of the actual call has been invalid already. Instead we now split argument processing into two parts. In the first step we only go up to the QAndroidJniObject, and we store those on the stack to outlive the JNI call. The second step then does the final conversion to the jobject handle.