IE: Backspace used to delete list item splits list in two

[Jakub Ś]

Reproducible in all versions of IE from CKEditor 3.0.

To Reproduce:

1. Create list in CKEditor with 4 items
2. Place the cursor at the end of item three and start pressing Backspace.

Result: When you remove the item list will be split on two.

NOTES:

1. In other browsers this behaviour got broken in CKEditor 3.6.3 rev [7392]. Reported here #8942
2. If you use delete key you will be able to remove the list item without splitting the list.

[Jakub Ś]

It seems we have few more tickets caused by this revision: #9009, #9933, #8942.