[perl #127101] Promise.allof() with empty argument is never kept

[via RT]

# New Ticket Created by  Sam S. 
# Please include the string:  [perl #127101]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=127101 >


This hangs indefinitely:

    my @promises;
    await Promise.allof(@promises);

Expected behavior: The await() should return immediately.

That would not just be the logical thing to do, but also make it consistent 
with synchronous junctions:

    my @values;
    say all(@values).Bool;  # True