Ignore Set/Map reordering in Diff and History UIs

[ghost]

Reordered elements in a Set or Map will register as a difference, but then are presented in the UI as having no actual differences. Don't count Set or Map reordering as a difference at all to reduce noise in the diff UIs.

[Sunjeet]

NOTE: we also saw in a list with no ordering changes, a diff was presented without any actual differences. Could be related.