Keep prototype maps in dictionary mode until ICs see them

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index 9e934f0a13fcfe11eff106da036461d70efe6175..ba7a2929440a6231ff80775f067226bae4305c7e 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -8097,8 +8097,7 @@ HInstruction* HGraphBuilder::BuildConstantMapCheck(Handle<JSObject> constant) {
 
 HInstruction* HGraphBuilder::BuildCheckPrototypeMaps(Handle<JSObject> prototype,
                                                      Handle<JSObject> holder) {
-  PrototypeIterator iter(isolate(), prototype,
-                         PrototypeIterator::START_AT_RECEIVER);
+  PrototypeIterator iter(isolate(), prototype, kStartAtReceiver);
   while (holder.is_null() ||
          !PrototypeIterator::GetCurrent(iter).is_identical_to(holder)) {
     BuildConstantMapCheck(PrototypeIterator::GetCurrent<JSObject>(iter));