The run against INBUXA's store hung printing "Waiting for pending task
AcmeRenewal(...)": the copy carries that server's task queue, and a renewal
due in 2026-11 will not come due while a test watches it.
Under NO_INSERT the wait now skips tasks that aren't due and ones that have
permanently failed, which leaves the tasks the test itself caused — a
restore in undelete_compat comes due at once — and gives up after a minute
with the offending task printed. A test that was really waiting on its own
work now fails on its assertion, which says more than a spinner.
Ordinary runs are untouched: system_tests, which waits on tasks throughout,
still passes in 135s.