Update HLL::Backend::Parrot to use new EvalPMC/PackfileView API.

Resolves issue #76, but requires a Parrot newer than
RELEASE_5_7_0-20-g07dfdb4.  See issue #76 for more details.

src/vm/parrot/HLL/Backend.nqp

@@ -114,19 +114,24 @@ class HLL::Backend::Parrot {
 
     method evalpmc($source, *%adverbs) {
         my $compiler := nqp::getcomp('PIR');
-        $compiler($source)
+        my $pbc := $compiler($source);
+        unless $pbc.is_initialized('init') {
+            for $pbc.subs_by_tag('init') -> $sub { $sub() }
+            $pbc.mark_initialized('init');
+        }
+        $pbc
     }
 
     method is_compunit($cuish) {
         !pir::isa__IPs($cuish, 'String')
     }
 
     method compunit_mainline($cu) {
-        $cu[0]
+        $cu.all_subs()[0]
     }
 
     method compunit_coderefs($cu) {
-        $cu
+        $cu.all_subs();
     }
 
     method recursion_limit($limit) {