I have seen this message once or twice, but since the actual error
message was not included, I cannot definitely say what’s going on.
I think it might be a race condition where the file with the specified
tmpname() already exists, but let’s be sure before we attempt to fix it.
BAIL_OUT produces a friendlier message explaining why the tests cannot
continue on the command line. `die` produces a cryptic message that some
test failed for some reason.
If a window with _NET_STARTUP_ID set is moved to another workspace, it
will delete any associated startup sequence immediately. This will also
occur if a window has a leader with _NET_STARTUP_ID set, if the leader
has no container (never been mapped).
A startup sequence may also be deleted if it's matched by
startup_workspace_for_window() and its 30-second timeout has elapsed.