Assert that caller columns are within bounds

Change-Id: Icf93bb5d57c9a4b6988a2ea34fc3ca23130d7eeb
diff --git a/sc/source/core/tool/scmatrix.cxx b/sc/source/core/tool/scmatrix.cxx
index 8bea649..6e0e9bb 100644
--- a/sc/source/core/tool/scmatrix.cxx
+++ b/sc/source/core/tool/scmatrix.cxx
@@ -1277,7 +1277,10 @@ public:
        mnStartIndex( nCol1 * aSize.row ),
        mnStopIndex( (nCol2 + 1) * aSize.row ),
        mnResult(ResultNotSet),
        mnIndex(0) {}
        mnIndex(0)
    {
        assert( nCol1 < aSize.column && nCol2 < aSize.column);
    }

    size_t getMatching() const { return mnResult; }