A start on a loaded host can take longer than the 10-second wait for
a line. The new output.lineBeforeExit waits until the line is written
or sww exits, so only the test binary's own timeout ends the wait. It
replaces the waits that span the start in runUntilStopped,
TestServesUntilToldToStop and TestLogLevelHoldsBackTheLessSevereProcessLines.
Model: opus-5-5