Notice if the test-runner dies

Currently, we seem to only care if the results collector errors.
We also should care if the test-runner died.

Authored-by: Rich Ercolani <rincebrain@gmail.com>
Co-authored-by: Rich Ercolani <rincebrain@gmail.com>
Reviewed-by: Damian Szuberski <szuberskidamian@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12998