Can't break <text> without <tspan>s of sodipodi:role="line"

Migrated from: https://bugs.launchpad.net/inkscape/+bug/167904
and https://bugs.launchpad.net/inkscape/+bug/186846

Steps to reproduce:

• open testcase.svg
• try to break either of the lines somewhere in the middle

What happened?

Does not work for any of the <text> elements, except the last one which has a <tspan> that has the attribute sodipodi:role="line".
Instead the text is split into two overlapping text elements.

What should have happened?

Should likely work for all lines, to achieve intuitive and user-friendly behavior.

Inkscape Version and Operating System:

• Inkscape Version: Confirmed in 0.92.4 and 1.0alpha (d0577fd1d4, 2019-03-24)
• Operating System: Windows 10