fix hangs caused by redoPlacement

After parsing a tile, it redoes placement for that tile if the angle has
changed since it started parsing. These redo calls were accidentally
done from the worker thread. Assigning the new work to `workRequest`
caused it to cancel itself.

Fix the problem by calling redoPlacement from the map thread.

src/mbgl/map/live_tile_data.cpp

@@ -55,6 +55,5 @@ void LiveTileData::parse() {
 
     if (getState() != State::obsolete) {
         setState(State::parsed);
-        redoPlacement();
     }
 }