This bug is inspired by bug#58928, but not the same, and repros after
Stefan's fix for that bug.  In fact, it repros in Emacs 27 as well.

See attached patch for repro steps as an ert test.  Essentially, either:

1) Create an overlay in an indirect buffer, set its 'evaporate property
   to t.
2) Delete text from the base buffer such that the overlay is empty.
3) Verify it is no longer in the indirect buffer (in fact, it remains as
   an empty overlay).

Repeat the above swapping the indirect and base buffers.  The bug goes
both ways.