Fixed a bug where IM reported wrong anchor rectangle

The problem was that in some cases, the cursor position was used to
calculate the anchor rectangle instead of the anchor position.

This caused selection handles to be shown at the wrong position.

Change-Id: I8d866b644fc3c4d530529b7f468d16ae1088cd98
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@theqtcompany.com>

src/widgets/widgets/qwidgetlinecontrol.cpp

@@ -441,7 +441,7 @@ QRect QWidgetLineControl::anchorRect() const
 {
     if (!hasSelectedText())
         return cursorRect();
-    return rectForPos(m_selstart < m_selend ? m_selstart : m_selend);
+    return rectForPos(m_cursor == m_selstart ? m_selend : m_selstart);
 }
 
 /*!