Make sure all geth processes are killed when stopping a local testnet

Author: danielrachi1

scripts/local_testnet/stop_local_testnet.sh

@@ -8,3 +8,7 @@ source ./vars.env
 PID_FILE=$TESTNET_DIR/PIDS.pid
 ./kill_processes.sh $PID_FILE
 rm -f $PID_FILE
+
+# Not all geth processes are killed when cleaning the PID_FILE. See:
+# https://github.com/sigp/lighthouse/issues/5382
+killall -HUP geth