CreateGCHandle throws when attempting to access a Il2CppSystem.Nullable that is null

[NathanKell]

On the native side, null nullables are genuinely null (reference type pointing at IntPtr.Zero). However, it appears that per the test here

Il2CppInterop/Il2CppInterop.Runtime/InteropTypes/Il2CppObjectBase.cs

Line 103 in aa36797

if (type.GetConstructor(new[] { typeof(IntPtr) }) is { } pointerConstructor)

in InitializeStore, they do not have a pointer-based constructor. That branches to the case where CreateGCHandle runs. However, when it runs, it finds the ptr to be IntPtr.Zero, and thus throws.