While actions of the target editor are properly deactivated when the
target is an ordinary, single-page editor, the same does not happen when
the target is a multi-page editor. In consequence, for example, you
cannot paste clipboard content into the overlay via the according
keyboard shortcut (CTRL+V), but it will paste into the target editor
instead.

With this change, the functionality to deactivate target editor actions
is extended to also deactivate the relevant global actions (cut, copy,
paste, etc.) that editors like multi-page editors fall back to.

Fixes to
https://github.com/eclipse-platform/eclipse.platform.ui/issues/2509