Remove EnhancedChangesList::arrow() and friends

Not used in core, the only usage outside removed in Ieb5bb6f9.

Also removed two now-unused files from skins/common/.

Bug: 69675
Change-Id: Ia0e9fc2af25af903db085f2a05c04dcd9aff213e
Merge "Remove EnhancedChangesList::arrow() and friends"