[perl #126913] *%_ slurpy unexpectedly wins against explicit named param in multi-dispatch

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# New Ticket Created by  Sam S. 
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Consider this code:

    multi x (:$a, *%_) { say 1 }
    multi x (:$b)      { say 2 }
    x :b

I would expect it to print 2, because the second candidate explicitly handles 
the :b named parameter, which is more specific than the *%_ catch-all slurpy.

But alas, it prints 1 in current Rakudo.


(This is rakudo version 2015.11-521-g782f4b6 built on MoarVM version 
2015.11-44-ge7edb06 implementing Perl v6.b.)