Reproduction steps:
1. Open the attached project
2. Create two Game Objects
3. Add an UndoBugScript to object A
4. Make object B a child of A
5. Add any component to A
6. Deselect A
7. Hit CTRL+F4 to run code that deletes B without registering an undo operation
8. Hit CTRL+Z to reselect A
9. Hit CTRL+Z to undo the component addition for A

Expected: Unity removes the added component from A
Actual: Unity crashes during GameObject::ActivateAwakeRecursivelyInternal

Reproducible on: 5.3.7p1, 5.4.4f1, 5.5.0p4, 5.5.0b3

Tested on Windows 10