QmlJS: Avoid accessing list after last element

Change-Id: I4d3f273c157db98615c9aee0152b04dd41f3e1fa
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>

src/libs/qmljs/qmljsdialect.cpp

@@ -298,7 +298,7 @@ void PathsAndLanguages::compact() {
             LanguageMerger merger;
             merger.merge(m_list.at(i - 1).language());
             do {
-                merger.merge(m_list.at(i++).language());
+                merger.merge(m_list.at(i).language());
                 if (++i == m_list.length())
                     break;
                 newPath = m_list.at(i).path();