[perl #126005] UNDO always fires for while, until, loop, and whenever

[via RT]

# New Ticket Created by  raiph 
# Please include the string:  [perl #126005]
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What I did
==========

while ++$ < 3 { UNDO say 'undo'; say 'done' }

What I got
==========

done
undo
done
undo

What I expected
===============

done
done

What I noticed
==============

while, until, loop, and whenever fire the UNDO phaser for their associated 
block regardless of whether the block succeeds or not.

$*PERL.perl.say shows version => 2015.7.1.735.g.781.c.2.c