Element links to data in ancestor views

Prompted by ATR-24052

The makeLink() helper function for views assumes that a piece of data accessed through viewX is actually associated with that view, when in fact it could be from an ancestor viewY or the main event-level store.

Changed the behaviour of makeLink() and the corresponding link remapping in the view merger helper to use the real location of the data.

Added a test for this, and tidied up the test script a little as well.