Steps to reproduce:

1. Open the attached project
2. Open a new scene (or just switch to some other scene besides Shader Callibration Scene)
3. Open Player Settings (Edit/Project Settings/Player)
4. Set the Graphics API to OpenGLCore (PlayerSettings -> disable Automatic Graphics API -> add OPENGLCore -> Move it to the top of the list)
5. Open the 'Shader Calibration Scene' under Assets folder
6. Unity editor will crash

Note: When the project is opened with 5.1.0b1, the Graphics API is set to OpenGLCore and then reopened with newer versions, it seems that you can then open the scene without a crash. However, if you switch back to DirectX and then switch again to OpenGLCore, the editor just crashes there.