on Github Cygwin VMs op/alarm rarely flaps

[wchristian]

In smoke runs on the Github Cygwin VMs op/alarm rarely flaps with error message:

FAILED--expected 5 tests, saw 0

This needs to be attempted to reproduce on the iron, and likely be converted into a failing TODO by wrapping the offending test in a loop to retry it more often.

This is related to #18193 and likely #18129.