Currently, a WPT test is considered failed if its status code is
anything other than 0, regardless of whether the test suite completed
running or not, and any subtests that haven't finished running are not
considered to be failures.
But a test can exit with a zero status code before it has completed
running, if the event loop has run out of tasks because of a bug in one
of the ops, leading to false positives. This change fixes that.
These reports can be consumed by tools like `wptreport` or
https://wpt.fyi. The old style report could be removed in a future PR
when wpt.deno.land is updated.
