tdf#150034 very slow opening pathological chart

revert part of
    commit 10c934147d469965dba6abc78efd02759a010b8e
    Author: Noel Grandin <noel.grandin@collabora.co.uk>
    Date:   Tue Apr 23 09:26:46 2019 +0200
    tdf#113266 slow opening XLS with 45 MB drawing
in this situation, avoiding setting all the rects dirty speeds up the
load from 70s to 1s.

Change-Id: Ia35119ff20ef5bded9a34f12cce453434dea4383
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/137688
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
(cherry picked from commit 613f6e75fbfcc024fc9c3732261cbf2cda6f4ad8)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/137964
Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>
diff --git a/svx/source/svdraw/svdpage.cxx b/svx/source/svdraw/svdpage.cxx
index b7aa877..ef189299 100644
--- a/svx/source/svdraw/svdpage.cxx
+++ b/svx/source/svdraw/svdpage.cxx
@@ -295,7 +295,8 @@ void SdrObjList::NbcInsertObject(SdrObject* pObj, size_t nPos)
    impChildInserted(*pObj);

    if (!mbRectsDirty) {
        mbRectsDirty = true;
        maSdrObjListOutRect.Union(pObj->GetCurrentBoundRect());
        maSdrObjListSnapRect.Union(pObj->GetSnapRect());
    }
    pObj->InsertedStateChange(); // calls the UserCall (among others)
}