Disable TestItemGraphDiff testCase1 because itemGraphForJSONResourceName doesn't find the bundle resource when run with testcoreobject-macosx.sh (perhaps because tools don't really have bundles?)

git-svn-id: http://svn.gna.org/svn/etoile/trunk/Etoile/Frameworks/CoreObject@10529 7b3f36aa-e6db-49c1-8b4c-66eac1997e64