Give back unfinished judging_runs/judgetasks in repeated rejudgings.

judgedaemons check in after start-up and after failed judgetask, see
https://github.com/DOMjudge/domjudge/blob/2222a867f99275cbdb8e81d4681e47522a29669f/judge/judgedaemon.main.php#L984

Checking in has the side effect that judgetasks that no longer need to
be executed are given back.

Previously, we checked whether either the judging or the rejudging was
valid, assuming that active rejudgings are marked as valid. This is not
true for repeated rejudgings where only the last instance is "valid".
For the check, it doesn't matter whether a rejudging is valid, only
whether a judging is associated with one.

Fixes #3069.

Author: meisterT

webapp/src/Controller/API/JudgehostController.php

@@ -175,7 +175,7 @@ public function createJudgehostAction(Request $request): array
             ->andWhere('jh.hostname = :hostname')
             ->andWhere('j.judgingid = jt.jobid')
             ->andWhere('jr.runresult IS NULL')
-            ->andWhere('j.valid = 1 OR r.valid = 1')
+            ->andWhere('j.valid = 1 OR j.rejudging IS NOT NULL')
             ->andWhere('j.result != :compiler_error')
             ->setParameter('hostname', $hostname)
             ->setParameter('compiler_error', 'compiler-error')