Make sure we can install symbols that originate from other compilatio…

…n units in lexicals.

src/Perl6/SymbolTable.pm

@@ -149,7 +149,7 @@ class Perl6::SymbolTable is HLL::Compiler::SerializationContextBuilder {
                 :pasttype('callmethod'), :name('get_lexinfo'),
                 PAST::Val.new( :value($block) )
             ),
-            ~$name, self.get_slot_past_for_object($obj)
+            ~$name, self.get_object_sc_ref_past($obj)
         );
         self.add_event(:deserialize_past($fixup), :fixup_past($fixup));
     }