[perl #129797] Channel.list does not honor .Slip

[via RT]

# New Ticket Created by  Wenzel Peppmeyer 
# Please include the string:  [perl #129797]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=129797 >


my $c = Channel.new;
$c.send((1,2,3).Slip);
$c.close;
dd (1,$c.list,2).join(':')
# OUTPUT«"1:1 2 3:2"␤»
# expected OUTPUT«"1:1:2:3:2"␤»