tdf#101313 Copy-paste table from writer to calc

With Merged Cells from Writer to Calc,
Cells Placed in Wrong Position (Wrong cell offsets).

regression from
    commit ed24564ce11683731b820c29d5a46e073ab7a2a7
    Author: Noel Grandin <noel@peralex.com>
    Date:   Thu Jul 19 15:22:31 2012 +0200
    SV_DECL_VARARR_SORT(ScRTFColTwips) o3tl::sorted_vector

Change-Id: I8c90c19f6a27a368fd5807b3eaab84ce820e26e5
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/163518
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
diff --git a/sc/source/filter/rtf/rtfparse.cxx b/sc/source/filter/rtf/rtfparse.cxx
index 9302aff..c56b3f7 100644
--- a/sc/source/filter/rtf/rtfparse.cxx
+++ b/sc/source/filter/rtf/rtfparse.cxx
@@ -101,8 +101,8 @@ inline void ScRTFParser::NextRow()

bool ScRTFParser::SeekTwips( sal_uInt16 nTwips, SCCOL* pCol )
{
    ScRTFColTwips::const_iterator it = aColTwips.find( nTwips );
    bool bFound = it != aColTwips.end();
    ScRTFColTwips::const_iterator it = aColTwips.lower_bound( nTwips );
    bool bFound = it != aColTwips.end() && *it == nTwips;
    sal_uInt16 nPos = it - aColTwips.begin();
    *pCol = static_cast<SCCOL>(nPos);
    if ( bFound )