P6Invocation should act more like a mutable iterator; we'll only clon…

…e it if we have to.

src/pmc/p6invocation.pmc

@@ -25,7 +25,7 @@ gets stuck into the lex pad to represent the the candidate list.
 static PMC *get_next_candidate(PARROT_INTERP, PMC *SELF) {
     PMC    *candidates, *current;
     INTVAL  position;
-    
+
     /* Get candidates and position. */
     GETATTR_P6Invocation_candidate_list(interp, SELF, candidates);
     GETATTR_P6Invocation_position(interp, SELF, position);
@@ -98,9 +98,6 @@ pmclass P6Invocation need_ext dynpmc group perl6_group {
         PMC      *lexpad, *first_candidate;
         opcode_t *addr;
 
-        /* We always operate on a clone of ourself. */
-        SELF = VTABLE_clone(interp, SELF);
-
         /* In the straightforward case, we know our first candidate right off the
          * bat; if not, use list. We also nullify first candidate so we hit the
          * candidate list next time we're used. */