skolemization is not threadsafe, fixing test

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@1622 85d21ef8-add0-11de-ae77-5bfb9c5a3f34
schema first order formula parser is not threadsafe - changed tests accordingly

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@1623 85d21ef8-add0-11de-ae77-5bfb9c5a3f34