[perl #122746] [BUG] Stringification of AST parameter not captured properly in postfix macro in Rakudo

[Christian Bartolomaeus via RT]

There is a passing test in S06-macros/unquoting.t now (cmp. commits 
https://github.com/perl6/roast/commit/054665cfb7 and 
https://github.com/perl6/roast/commit/d6570538ae).

I'm closing this ticket now.