[perl #38167] [TODO] Tests - Calling Conventions/HLL Mappings

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# New Ticket Created by  Will Coleda 
# Please include the string:  [perl #38167]
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# <URL: https://rt.perl.org/rt3/Ticket/Display.html?id=38167 >


Tests need to be written to verify that HLL mappings are properly  
used for :slurpy syntax.

Something like:

.HLL 'Foo', 'foo_group'

.sub 'main' :main

   joe(1,2,3,4)

.end

.sub 'joe'
   .param pmc argv :slurpy

   $S0 = typeof argv
   print $S0
   print_newline
.end


which would print whatever the type of the ResizablePMCArray mapping  
for the HLL 'Foo' was.

(This also requires a HLL mapping for a language, preferably via the  
C-level API vs. PIR-only)