AutoTest: Fix wrong caching of text layout

The text layout must get recalculated also when the width
of the underlying model index has changed.

Fixes: QTCREATORBUG-24236
Change-Id: I4ded56832c765320b6845cf35ad61453875dad50
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/autotest/testresultdelegate.h

@@ -52,6 +52,7 @@ private:
     mutable QFont m_lastProcessedFont;
     mutable QTextLayout m_lastCalculatedLayout;
     mutable int m_lastCalculatedHeight;
+    mutable int m_lastWidth = -1;
 
     class LayoutPositions
     {