[perl #120397] [BUG] Null PMC access (Parrot) and segfault (JVM) when assigning to a variable "declared" in a subsignature in a variable declaration in Rakudo

[Christian Bartolomaeus via RT]

I added a test to S04-declarations/my.t with commit 
https://github.com/perl6/roast/commit/25f2964446

It only tests that there is no NullPointerException (or no segfault which would 
abort the test) -- everything else passes.

I'm closing this ticket as 'resolved'.