Revert "sw_redlinehide_3: apparently a live SwNodeNum always has a parent"

This reverts commit 6eebecf3.

The problem is that *during* RemoveFromList(), the IsInList() is called
after the parent pointer is reset to null.

e.g. during export of ooo67907-1.doc to .doc.

SwTextNode::IsInList() const (this=0x57a3b30) at sw/source/core/txtnode/ndtxt.cxx:4352
SwTextNode::NumRuleChgd() (this=0x57a3b30) at sw/source/core/txtnode/ndtxt.cxx:2863
SwNodeNum::NotifyNode() (this=0x5804f80) at sw/source/core/SwNumberTree/SwNodeNum.cxx:211
SwNumberTreeNode::Notify() (this=0x5804f80) at sw/source/core/SwNumberTree/SwNumberTree.cxx:1068
SwNumberTreeNode::NotifyInvalidChildren() (this=0x52f1820f) at sw/source/core/SwNumberTree/SwNumberTree.cxx:1088
SwNumberTreeNode::NotifyInvalidChildren() (this=0x57e4ab0) at sw/source/core/SwNumberTree/SwNumberTree.cxx:1111
SwNumberTreeNode::RemoveChild(SwNumberTreeNode*) (this=0x52f1820f, pChild=0x5804f80) at sw/source/core/SwNumberTree/SwNumberTree.cxx:618
SwNumberTreeNode::RemoveMe() (this=0x5804f80) at sw/source/core/SwNumberTree/SwNumberTree.cxx:648
SwListImpl::RemoveListItem(SwNodeNum&) (rNodeNum=...) at sw/source/core/doc/list.cxx:151
SwList::RemoveListItem(SwNodeNum&) (rNodeNum=...) at sw/source/core/doc/list.cxx:251
SwTextNode::RemoveFromList() (this=0x57a3b30) at sw/source/core/txtnode/ndtxt.cxx:4328
(anonymous namespace)::HandleSetAttrAtTextNode::HandleSetAttrAtTextNode(SwTextNode&, SfxItemSet const&) (this=0x7ffffcc90aa0, rTextNode=..., rItemSet=SfxItemSet of pool 0x51799b0 with parent 0x0 and Which ranges: [(72, 72)] = {...}) at sw/source/core/txtnode/ndtxt.cxx:4751
SwTextNode::SetAttr(SfxItemSet const&) (this=0x57a3b30, rSet=SfxItemSet of pool 0x51799b0 with parent 0x0 and Which ranges: [(72, 72)] = {...}) at sw/source/core/txtnode/ndtxt.cxx:4917

Change-Id: I5a2775f397da171cde23cbf42f7e95da958987e8
Reviewed-on: https://gerrit.libreoffice.org/64448
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>
(cherry picked from commit b3e77dd9)
Reviewed-on: https://gerrit.libreoffice.org/64450Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/source/core/txtnode/ndtxt.cxx

@@ -4342,8 +4342,6 @@ void SwTextNode::RemoveFromListRLHidden()
 
 bool SwTextNode::IsInList() const
 {
-    // it looks like an unconnected Num can't happen, except in the undo-array
-    assert(!GetNum() || GetNum()->GetParent() || !GetNodes().IsDocNodes());
     return GetNum() != nullptr && GetNum()->GetParent() != nullptr;
 }