Fix UI in generic wxListCtrl when pressing cursor arrows while editing.

Fix UI in generic wxListCtrl when pressing cursor arrows while editing.

Pressing Up/Down keys while editing an item changed the selection but left the
in-place editing control on the previously selected item which was just wrong.
Ignore these keys to avoid it.

Notice that there is an underlying bug somewhere in wxGTK because we shouldn't
be getting these events in the first place while the in-place editing text
control has focus but it doesn't seem easy to fix so work around it here.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70315 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775