[perl #126421] Multi-range regex character class <[a..z0..9]> does not respect case-insensitive matching

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# New Ticket Created by  Sam S. 
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This unexpectedly fails to match the capital A:

    ➜  say "Aa1" ~~ /:i <[a..z0..9]>+/
    ｢a1｣

*Without* the second range in the character class, it works as expected:

    ➜  say "Aa1" ~~ /:i <[a..z]>+/
    ｢Aa｣

(This is perl6 version 2015.09-433-g26617f9 built on MoarVM version 
2015.09-79-gee9fc2b).