How to reproduce:
1. Open the attached Project "GetFunctionPointerReturnsZero.zip"
2. In the Project Settings, under Player -> Other Settings set Scripting Backend to IL2CPP
3. Build and Run the Project
4. Observe the Player.log

Expected result: GetFunctionPointer() returns a proper value
Actual result: GetFunctionPointer() returns 0

Reproducible with: 6000.0.11f1
Not reproducible with: 2021.3.40f1, 2022.3.37f1 ("Unsupported internal call for IL2CPP:RuntimeMethodHandle::GetFunctionPointer - "This icall is not supported by il2cpp. Use Marshal.GetFunctionPointerForDelegate instead."" is thrown when using GetFunctionPointer())

Notes:
- In the example Project GetFunctionPointer() is used on the method UnityEngine.Object.FindObjectsByType()