ctf: Fix lost events timestamp in CTFPacketReader

ctf: Fix lost events timestamp in CTFPacketReader

The lost events should be inserted after the last event in the packet,
not before the first event in the packet.

This was a regression where the changes to CTFStreamInputPacketReader
from https://git.eclipse.org/r/50683 were not ported to CTFPacketReader.

Change-Id: I055887b02212bd43052d36fbbd0dde3ca36edb6e
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/61598
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-by: Hudson CI