Resolve "Add a shutdown hook that stops the GC if it was not stopped yet"

Closes #1564

See merge request main/Sumatra!1451

sumatra-commit: 13a92640721d73ff8c2df5eaf36e6c178406a478

modules/moduli-referee/src/main/java/edu/tigers/sumatra/referee/SslGameControllerProcess.java

@@ -35,6 +35,7 @@ public class SslGameControllerProcess implements Runnable
 	private final int gcUiPort;
 	private final String publishAddress;
 	private final String timeAcquisitionMode;
+	private final Thread shutdownHook = new Thread(this::stop);
 
 	private Process process = null;
 
@@ -57,6 +58,8 @@ public class SslGameControllerProcess implements Runnable
 			return;
 		}
 
+		Runtime.getRuntime().addShutdownHook(shutdownHook);
+
 
 		Path engineConfig = Path.of("config", "engine.yaml");
 		Path engineConfigDefault = Path.of("config", "engine-default.yaml");
@@ -111,6 +114,7 @@ public class SslGameControllerProcess implements Runnable
 			log.warn("game-controller has returned a non-zero exit code: {}", p.exitValue());
 		}
 		log.debug("game-controller process thread finished");
+		Runtime.getRuntime().removeShutdownHook(shutdownHook);
 	}