tdf#126340 sw_redlinehide: only move merged frames in JoinPrev

The problem was that the first and second node were not actually merged
by a redline, so moving the frames doesn't make sense.

(regression from 41d8ca9686c7c184f586e99674b443c34bfd4f33)

Change-Id: Ib401e4b0b2b207666f65c038ab5c346807bfea92
Reviewed-on: https://gerrit.libreoffice.org/76125
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>
(cherry picked from commit 91b344b0346347ac40d2d6fa03a03e92d2e9f252)
Reviewed-on: https://gerrit.libreoffice.org/76149
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit 680c4eac7a39b7e039d7828a3cac839395b9a36e)
Reviewed-on: https://gerrit.libreoffice.org/76533
Reviewed-by: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>
Reviewed-by: Xisco Faulí <xiscofauli@libreoffice.org>
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
diff --git a/sw/source/core/doc/docedt.cxx b/sw/source/core/doc/docedt.cxx
index baf3280..791736f 100644
--- a/sw/source/core/doc/docedt.cxx
+++ b/sw/source/core/doc/docedt.cxx
@@ -414,7 +414,8 @@ bool sw_JoinText( SwPaM& rPam, bool bJoinPrev )
            }
            // delete the Node, at last!
            SwNode::Merge const eOldMergeFlag(pOldTextNd->GetRedlineMergeFlag());
            if (eOldMergeFlag == SwNode::Merge::First)
            if (eOldMergeFlag == SwNode::Merge::First
                && !pTextNd->IsCreateFrameWhenHidingRedlines())
            {
                sw::MoveDeletedPrevFrames(*pOldTextNd, *pTextNd);
            }
diff --git a/sw/source/core/txtnode/ndtxt.cxx b/sw/source/core/txtnode/ndtxt.cxx
index 691c20f..cced718 100644
--- a/sw/source/core/txtnode/ndtxt.cxx
+++ b/sw/source/core/txtnode/ndtxt.cxx
@@ -1126,7 +1126,8 @@ void SwTextNode::JoinPrev()
            pDoc->CorrAbs( aIdx, SwPosition( *this ), nLen, true );
        }
        SwNode::Merge const eOldMergeFlag(pTextNode->GetRedlineMergeFlag());
        if (eOldMergeFlag == SwNode::Merge::First)
        if (eOldMergeFlag == SwNode::Merge::First
            && !IsCreateFrameWhenHidingRedlines())
        {
            sw::MoveDeletedPrevFrames(*pTextNode, *this);
        }