TT#46902 Check that /var/cores is not there

We have not been using /var/cores for a while, since starting to use
systemd-coredump around releases mr6.2 or mr6.3, so this file is now
unnecessary.

However, there was a script creating the file and this test ensuring that it
existed and no core dump files were present.

It's not particularly tied to TT#46902, but it got discovered while working on
it and the task also touches the area of "core dump" files.

Change-Id: If75fcfa28a75359033ab4efddec503da401e61bb

templates/110_filesys-cores.yaml.tt2

@@ -1,20 +1,7 @@
 file:
   /var/cores:
-    exists: true
-    mode: "1777"
-    owner: root
-    group: root
-    filetype: directory
-    contains: []
-
-command:
-  "ls /var/cores/":
-    exit-status: 0
-    stdout:
-    - "!/^core\\..+/"
-    stderr: []
+    exists: false
 
-file:
   /var/lib/systemd/coredump:
     exists: true
     mode: "0755"