Should not remove intersection nodes when simplifying

[naoliv]

Using this example:

Selecting all the ways at the same time and using simplify area we have this:

See that a lof of intersection nodes were removed (it works properly with individual ways however).
It shouldn't remove the intersection nodes when multiple ways are selected.

[skyper]

Smallered pictures

[*Martin*]

Fixed in [o30791:30792].