fdo#51777: add a hack for 1 twip DOUBLE borders:

Arguably such annoyingly thin double borders don't make much sense
anyway, because they're essentially 2 hairlines with ~no space between,
but unfortunately older LO versions are able to create them;
since the refactoring in 2d045cdb,
which changed the BorderWidthImpl::Get* methods to return 0 due to
rounding, they were ignored at least in the HTML import, which is a
regression.
So add a special purpose hack that essentially rounds up the first line
to 1 but not the other lines so the visual result is a hairline single
border.

Change-Id: I20ac4675bcf67ea58a6931a40bff3605390e9c0d

svtools/source/control/ctrlbox.cxx

@@ -328,6 +328,10 @@ long BorderWidthImpl::GetLine1( long nWidth ) const
         result = std::max<long>(0,
                     static_cast<long>((m_nRate1 * nWidth) + 0.5)
                         - (nConstant2 + nConstantD));
+        if (result == 0 && m_nRate1 > 0.0 && nWidth > 0)
+        {   // fdo#51777: hack to essentially treat 1 twip DOUBLE border
+            result = 1;  // as 1 twip SINGLE border
+        }
     }
     return result;
 }

sw/source/filter/html/htmltab.cxx

@@ -2072,8 +2072,7 @@ void HTMLTable::SetBorders()
 sal_uInt16 HTMLTable::GetBorderWidth( const SvxBorderLine& rBLine,
                                   sal_Bool bWithDistance ) const
 {
-    sal_uInt16 nBorderWidth = rBLine.GetOutWidth() + rBLine.GetInWidth() +
-                    rBLine.GetDistance();
+    sal_uInt16 nBorderWidth = rBLine.GetWidth();
     if( bWithDistance )
     {
         if( nCellPadding )