Add a built-in timeout mechanism to valgrind-checks

If things go wrong and a run of valgrind-checks gets stuck, it's
hard to terminate and clean after it properly because it runs as
root. In a container, but that doesn't make a difference. To
avoid such issues, let's make sure the `bash` process running the
valgrind checks kills itself after a period of time unless it
finishes properly (succeeding or failing).

Ticket: CFE-4416
Changelog: None
(cherry picked from commit 079c633)

tests/valgrind-check/valgrind.sh

@@ -58,6 +58,14 @@ function check_masterfiles_and_inputs {
 set -e
 set -x
 
+# In case things go wrong and this hangs, let's make sure things get properly
+# cleaned up from here rather than relying on the outer environment doing the
+# cleanup. In case this runs in a container, it could be a big
+# difference. Especially in a case of an SPC.
+{ sleep 30m && kill -9 $$; } &
+auto_destruct_pid=$!
+trap "kill $auto_destruct_pid" EXIT
+
 # Assume we are in core directory
 if [ -f ./configure ] ; then
   ./configure -C --enable-debug