Backwards navigation and hierarchy view have different (and worse) rules about what they show compared to forward navigation

[lognaturel]

Software and hardware versions

Collect v1.30.1, master

Problem description

Backwards navigation and hierarchy view have different (and worse) rules about what they show compared to forward navigation.

Steps to reproduce the problem

1. Create a form with a repeat that could have no contents for some instances. E.g. vegetables.xlsx
2. Fill out the form such that some instances are relevant and some are not. For example, select two vegetables in the attached form.
3. Swipe forward to see the expected behavior.
4. Swipe back to see a screen for each repeat instance, even those with no contents.
5. Go to the hierarchy view from one of the "ghost" repeats to see more badness.

bug.mp4

Expected behavior

If there are no visible notes in a repeat instance, that whole repeat instance should be skipped in all cases. The forward navigation behavior should be replicated.

Other information

Related to #4457.

[lognaturel]

This variation works as expected (other than #4570).

[dimwight]

Had a look at this but made little headway.
XLSForm didn't like vegetables.xlsx at all to start with, then the repeats didn't work.