To reproduce:
1. Open attached project
2. Build it to iOS
3. Try pressing the button
The button will call a function, which causes the bug (the screenshot of te function is also attached)
Notice that an ExecutionEngineException appears in the console (full text in the edit)
The exception doesn't appear while running in Editor.

Tested on IL2CPP backend, not tested on mono because the application crashes at splash screen (which is most likely a differrent bug)

Also tested with engine code stripping turned off, which resulted in the same exception.

Reproduced on: 5.6.0b7

Not tested on earlier versions because when opening the same project in 5.5 (and even other older of 5.6) there are 200+ compilation errors.