Steps to reproduce:
1. Open the attached project (IL2CPPTesting.zip)
2. Switch platform to Windows Store
3. Build for WSA Universal 10 SDK, Build type - XAML
4. Build to the case_896587-TestingUnityUnload\TestingUnityUnload_WSA folder
5. Open Visual Studio solution
6. Deploy on local machine (Debug x64)
7. Click the 'Load Unity Component' button to load the engine and observe the memory increase in the right panel when the scene loads
8. Click 'Unload Unity Component' to call Application.Unload but observe that the scene is still present and the memory usage does not decrease

Expected result: UnityEngine.Application.Unload should unload the Unity Runtime
Actual result: UnityEngine.Application.Unload does not unload the Unity Runtime

Reproduced with: 5.5.1f1, 5.5.3f1, 5.6.0f3, 2017.1.0a6