Always run memtool at the start

JOURNAL.md

@@ -1038,3 +1038,5 @@ Let's see if we can reproduce it again in the same position.
     iter 26, nblocks 21, nbytes 50.2M (A)
     iter 27, nblocks 22, nbytes 53.8M (A)
 
+Let's make it automatic, so we only need to boot and confirm that it
+hangs. Just in case we can make it not hang by a miracle.

lagarto-ox.nix

@@ -96,6 +96,11 @@
         sh -c 'hb=0; while [ 1 ]; do let hb=$hb+1; devmem 0x1bfff0000 32 $hb; done' &
       ''
       +
+      # Run our memtool to hang the kernel here.
+      ''
+        memtool
+      ''
+      +
       # Disable proactive compaction. May be better to disable CONFIG_COMPACTION.
       ''
         echo 0 > /proc/sys/vm/compaction_proactiveness