[perl #131639] [BUG] Junction:D.iterator returns an iterator that .pulls-one a Mu type object

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# New Ticket Created by  Zoffix Znet 
# Please include the string:  [perl #131639]
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# <URL: https://rt.perl.org/Ticket/Display.html?id=131639 >


Originally found this in behaviour of Z meta operator:

    <Zoffix__> m: dd <a b c>.any Z <d e f>.any
    <camelia> rakudo-moar 10f840: OUTPUT: «((Mu, Mu),).Seq␤»

Which works fine with X metaoperator:

    <Zoffix__> m: dd <a b c>.any X <d e f>.any
    <camelia> rakudo-moar 10f840: OUTPUT: «((any("a", "b", "c"), any("d", "e", 
"f")),).Seq␤»

I dug a bit and found the cause to be in Any.iterator:

    <Zoffix__> m: dd Seq.new: any('x').iterator
    <camelia> rakudo-moar 10f840: OUTPUT: «(Mu,).Seq␤»

But after that I lost the trail and unsure where the bug is hiding...