Fix yield inside with

src/scopes.cc

Index: src/scopes.cc
diff --git a/src/scopes.cc b/src/scopes.cc
index 10548f99381e933d3dc9ccd3063e25fdea38c378..5ad970ad814f1d6ffc06e4b7b04cac57806fa1a8 100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -726,7 +726,9 @@ int Scope::ContextChainLength(Scope* scope) {
   int n = 0;
   for (Scope* s = this; s != scope; s = s->outer_scope_) {
     ASSERT(s != NULL);  // scope must be in the scope chain
-    if (s->num_heap_slots() > 0) n++;
+    if (s->is_with_scope() || s->num_heap_slots() > 0) n++;
+    // Catch scopes always have heap slots.
+    ASSERT(!s->is_catch_scope() || s->num_heap_slots() > 0);
   }
   return n;
 }