Make sure Regex::Cursor ends up in an SC.

Author: jnthn

src/Regex/Cursor.pir

@@ -46,6 +46,11 @@ grammars.
     set_global "$?CLASS", type_obj
     how = get_how type_obj
 
+    # Add to serialization context.
+    $P0 = nqp_get_sc "__REGEX_CORE_SC__"
+    nqp_set_sc_object "__REGEX_CORE_SC__", 0, type_obj
+    nqp_set_sc_for_object type_obj, $P0
+    
     # XXXNS Old namespace handling installation, during migration to new.
     set_hll_global ["Regex"], "Cursor", type_obj