RunLoop must outlive Object

~Object is likely to join threads that want to dispatch results
back to this RunLoop. This happens, for example, when MapContext
is destructed: it joins the worker threads, which need to complete
work before shutting down.

src/mbgl/util/thread.hpp

@@ -122,12 +122,12 @@ void Thread<Object>::run(P&& params, index_sequence<I...>) {
     uv::loop l;
 
     {
-        Object object_(l.get(), std::get<I>(std::forward<P>(params))...);
-        object = &object_;
-
         RunLoop loop_(l.get());
         loop = &loop_;
 
+        Object object_(l.get(), std::get<I>(std::forward<P>(params))...);
+        object = &object_;
+
         running.set_value();
         l.run();