How to reproduce:
1. Open the user-submitted project
2. Add the "hexagon-png-other-resolutions-276-240-pixels-553" sprite from the "Images" folder to the Hierarchy
3. In the Inspector change the Y Position to 1, X Rotation to 270 and Scale on all axis to 0.2
4. Add a Polygon Collider component to the sprite

Expected result: The Polygon Collider is added successfully
Actual result: The Editor crashes while adding the component

Reproduced in: 2018.2.0b3, 2018.1.0f2, 2017.4.2f2, 2017.2.3f1, 2017.1.3p4

Note: Does not seem to reproduce with non-transparent textures or different colliders, transparency and the rotation seem key to the crash

Verified in: 2018.3.0a2