jenkins: kill potentially leftover processes (#24078)

* jenkins: kill potentially leftover processes

* cleaner

* oops

* escape

* might already be dead

Jenkinsfile

@@ -19,8 +19,13 @@ fi
 ln -snf ${env.TEST_DIR} /data/pythonpath
 
 if [ -f /EON ]; then
+  # kill all old procs in the openpilot cpuset
+  while read p; do
+    kill "\$p" || true
+  done < /dev/cpuset/app/tasks
+
   echo \$\$ > /dev/cpuset/app/tasks || true
-  echo \$PPID > /dev/cpuset/app/tasks || true
+
   mkdir -p /dev/shm
   chmod 777 /dev/shm
 fi