ofz: special case max index for cSymbol

Change-Id: Ia5fb036196b0cff0739789e691a36d294660540b
Reviewed-on: https://gerrit.libreoffice.org/44759Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>

sc/source/core/tool/compiler.cxx

@@ -3266,6 +3266,8 @@ bool ScCompiler::IsReference( const OUString& rName, const OUString* pErrRef )
             return true;
         // Now try with a symbol up to the range operator, rewind source
         // position.
+        if (mnRangeOpPosInSymbol == MAXSTRLEN-1)
+            return false;
         sal_Int32 nLen = mnRangeOpPosInSymbol;
         while (cSymbol[++nLen])
             ;