Revert "Do not use schematic object UUID comparisons when UUIDs are mutable."

This reverts commit 1dfe3ebc54.

eeschema/sch_item.cpp

@@ -442,14 +442,11 @@ int SCH_ITEM::compare( const SCH_ITEM& aOther, int aCompareFlags ) const
         return 0;
     }
 
-    if( isUuidImmutable() )
-    {
-        if( m_Uuid < aOther.m_Uuid )
-            return -1;
+    if( m_Uuid < aOther.m_Uuid )
+        return -1;
 
-        if( m_Uuid > aOther.m_Uuid )
-            return 1;
-    }
+    if( m_Uuid > aOther.m_Uuid )
+        return 1;
 
     return 0;
 }

eeschema/sch_item.h

@@ -665,19 +665,6 @@ protected:
 
     void getSymbolEditorMsgPanelInfo( EDA_DRAW_FRAME* aFrame, std::vector<MSG_PANEL_ITEM>& aList );
 
-    /**
-     * Return the status of the #SCH_ITEM objects UUID immutability.
-     *
-     * This method is used by compare() to determine if the object's UUIDs should be compared.
-     * Most #SCH_ITEM object UUIDs are created at run time an therefore should not be compared
-     * so the default returns false.  Override this method for #SCH_ITEM objects that have
-     * immutable UUIDs.
-     *
-     * @retval true if the item's UUID is immutable.
-     * @retval false if the item's UUID is not immutable.
-     */
-    virtual bool isUuidImmutable() const { return false; }
-
     /**
      * Provide the draw object specific comparison called by the == and < operators.
      *

eeschema/sch_pin.cpp

@@ -1887,11 +1887,6 @@ wxString SCH_PIN::getItemDescription( ALT* aAlt ) const
 }
 
 
-bool SCH_PIN::isUuidImmutable() const
-{
-    // SCH_SYMBOL pin UUIDs are immutable.  LIB_SYMBOL pins UUIDs are not immutable.
-    return ( static_cast<SCH_SYMBOL*>( GetParent() ) != nullptr );
-}
 
 
 int SCH_PIN::compare( const SCH_ITEM& aOther, int aCompareFlags ) const

eeschema/sch_pin.h

@@ -333,9 +333,6 @@ protected:
      */
     void printPinElectricalTypeName( const RENDER_SETTINGS* aSettings, const VECTOR2I& aPosition,
                                      PIN_ORIENTATION aOrientation, bool aDimmed );
-
-    virtual bool isUuidImmutable() const override;
-
     std::ostream& operator<<( std::ostream& aStream );
 
 private:

eeschema/symbol.h

@@ -208,8 +208,6 @@ public:
     std::vector<int> ViewGetLayers() const override;
 
 protected:
-    virtual bool isUuidImmutable() const override { return true; }
-
     TRANSFORM     m_transform;             ///< The rotation/mirror transformation.
 
     int           m_pinNameOffset;         ///< The offset in mils to draw the pin name.  Set to