run-tests: report tests as failed when run-test raises an error

Before no message was returned to the main thread. No result was registered
and no new thread was started.
This does not happen when running normal. But when fiddling around with
the test infrastructure, this helps a lot.

tests/run-tests.py

@@ -1077,6 +1077,9 b' def scheduletests(options, tests):'
             done.put(runone(options, test, count))
         except KeyboardInterrupt:
             pass
+        except: # re-raises
+            done.put(('!', test, 'run-test raised an error, see traceback'))
+            raise
 
     try:
         while tests or running: