Recover test case for T11547

Commit 98c7749c has reverted commit 59d7ee53, including the test that that file added. That test case is still valuable, so I am re-adding I add it with it’s current (broken) behavior so that whoever fixes it intentionally or accidentially will notice and then commit the actual desired behavior (which is kinda unspecified, see #20455 (comment 382030))