Ininite recursion in TreeLayout when the "tree" is a grap with cycles

[NicolasAnquetil]

Test do not show it I am not sure why,
but in RSAbstractVerticalTreeLayout >> translate:by: call to childrenFor: can lead to an infinite recursion

Solution would be to use computeChildrenFor:

[JanBliznicenko]

Hello, this seems to be matter of https://github.com/pharo-graphics/RoassalLayouts
I have actually fixed it (or rather hotfixed it - graphs with loops produce quite ugly layouts), but it is only available in the master branch, not Pharo13 branch, as the backporting PR never got merged: pharo-graphics/RoassalLayouts#4