Demo application that demonstrates issues that appear in Mapbox under low memory conditions in flutter app

flutter/flutter#48182

Steps to reproduce the issue

1. Open the app on a real device. For example, iPad mini 2 (Model A1489)
2. Perform some actions on the map during 10 seconds: zoom, pan etc.
3. After 10 seconds following can happen:
   1. Crash
   2. Drawing artifacts
   3. Black screen