Fixed array access in tests.



git-svn-id: https://quantlib.svn.sourceforge.net/svnroot/quantlib/trunk/QuantLib@18452 8618b1d8-e22c-0410-b026-96a5dba3e089
Prevented warning in VC++10.



git-svn-id: https://quantlib.svn.sourceforge.net/svnroot/quantlib/trunk/QuantLib@18453 8618b1d8-e22c-0410-b026-96a5dba3e089