Game crash when ilhook Level.TransitionRoutine

```cs
public void OnLoad() {
new ILHook(typeof(Level).GetMethod("TransitionRoutine", BindingFlags.Instance | BindingFlags.NonPublic).GetStateMachineTarget(), il => {});
}
```

```
Ver 1.4.0.0-xna [Everest: 3014-azure-106d7]
08/27/2021 15:24:16
System.TypeLoadException: Could not load type 'Celeste.patch_Level+d__25' from assembly 'Celeste, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.
at System.Reflection.CustomAttribute._CreateCaObject(RuntimeModule pModule, IRuntimeMethodInfo pCtor, Byte** ppBlob, Byte* pEndBlob, Int32* pcNamedArgs)
at System.Reflection.CustomAttribute.CreateCaObject(RuntimeModule module, IRuntimeMethodInfo ctor, IntPtr& blob, IntPtr blobEnd, Int32& namedArgs)
at System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeModule decoratedModule, Int32 decoratedMetadataToken, Int32 pcaCount, RuntimeType attributeFilterType, Boolean mustBeInheritable, IList derivedAttributes, Boolean isDecoratedTargetSecurityTransparent)
at System.Reflection.CustomAttribute.GetCustomAttributes(RuntimeMethodInfo method, RuntimeType caType, Boolean inherit)
at System.Reflection.RuntimeMethodInfo.GetCustomAttributes(Boolean inherit)
at MonoMod.Utils.Extensions.GetStateMachineTarget(MethodInfo method)
at Celeste.Mod.SpeedrunTool.SaveLoad.StateManager.OnLoad()
```