[perl #130575] [BUG] Variables inside a try {} block used with `andthen` don't always get updated to correct values

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# New Ticket Created by  Zoffix Znet 
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<ZoffixW> m: sub itcavuc ($c) { (try say $c) andthen 42 }; itcavuc $_ for 2, 4, 
6
<camelia> rakudo-moar 7d5bbe: OUTPUT«2␤4␤6␤»
<ZoffixW> m: sub itcavuc ($c) { try {say $c} andthen 42 }; itcavuc $_ for 2, 4, 
6
<camelia> rakudo-moar 7d5bbe: OUTPUT«2␤2␤4␤»

The block `try {}` seems to have repeated `2` and missing `6` in the output. 
The bug seems to occur with a combination of a block form of `try` and 
`andthen` (which thunks)

A few more cases: https://irclog.perlgeek.de/perl6/2017-01-17#i_13936831