How to reproduce:
1. Open the attached "SmallerReproProject' project
2. Open the "Sandbox" scene and enter playmode

Expected result: Playmode is entered
Actual result: Crash occurs

Notes:
1. Couldn't reproduce this with 5.5 version of Unity, since it didn't support the 9-slice Sprite rendering which was introduced in 5.6.0b3. And after commenting SpriteRenderer.size methods, the project just provides a lot of "NullReferenceException" errors, but stops crashing
2. Commenting 41st line in a BaseActionPlayerComponent.cs script seems to solve the crash. -> _input = _player.GetComponent<BaseInput>();

Reproducible with - 2017.1.0b1, 5.6.0p1, 5.6.0b3