Remove unused Frame::dumpDebug()

Should be operator<<(QDebug) anyway if we need it

src/private/Frame.cpp

@@ -396,15 +396,6 @@ int Frame::dbg_numFrames()
     return s_dbg_numFrames;
 }
 
-void Frame::dumpDebug()
-{
-    qDebug() << "        Frame:" << (void*)this;
-    qDebug() << "            layoutItem=" << m_layoutItem << "; num=" << m_tabWidget->numDockWidgets();
-    for (auto dw : dockWidgets()) {
-        qDebug() << "            dockwidget=" << dw << "; dw->lastPositions=" << dw->lastPositions();
-    }
-}
-
 bool Frame::beingDeletedLater() const
 {
     return m_beingDeleted;

src/private/Frame_p.h

@@ -185,9 +185,6 @@ public:
     ///@brief For tests-only. Returns the number of Frame instances in the whole application.
     static int dbg_numFrames();
 
-    ///@brief for debug only, prints some debug information
-    void dumpDebug();
-
     /**
      * @brief Returns whether a deleteLater has already been issued
      */