With a member of a compound path selected, Paste in Front and Paste in Back
put the clipboard's objects next to that member, inside the compound path,
whatever they were. A pasted group, compound path or type object then sat
inside a compound path, which holds only paths. The model-based test
`random_command_sequences` stops on this with "compound #N has a non-path
child".
When the clipboard holds anything other than paths, the objects now go
right above or below the compound path. Paths still go next to the member,
inside the compound path.