Write object number of next free reference in xref streams

DEVSIX-1428

Autoported commit.
Original commit hash: [f42396e6c]

Author: yulian-gaponenko

itext/itext.kernel/itext/kernel/pdf/PdfXrefTable.cs

@@ -241,7 +241,8 @@ protected internal virtual void WriteXrefTableAndTrailer(PdfDocument document, P
                         if (reference.IsFree()) {
                             xrefStream.GetOutputStream().Write(0);
                             //NOTE The object number of the next free object should be at this position due to spec.
-                            xrefStream.GetOutputStream().Write(IntToBytes(0));
+                            System.Diagnostics.Debug.Assert(reference.GetOffset() < int.MaxValue);
+                            xrefStream.GetOutputStream().Write(IntToBytes((int)reference.GetOffset()));
                             xrefStream.GetOutputStream().Write(ShortToBytes(reference.GetGenNumber()));
                         }
                         else {

port-hash

@@ -1 +1 @@
-422c699fa551196e2e0f3bfdcef6aa90c55e04dd
+f42396e6c27ad4861e909714fe083fdbf730fdfc