Only generate a single normal IC per kind per slow-mode map.

src/stub-cache.cc

Index: src/stub-cache.cc
diff --git a/src/stub-cache.cc b/src/stub-cache.cc
index 78a217bb61a06b124ab19d511fd9657f2c27acc0..eb7195213a9710fe677ce34dcceb107cae249695 100644
--- a/src/stub-cache.cc
+++ b/src/stub-cache.cc
@@ -132,8 +132,13 @@ Handle<Code> PropertyHandlerCompiler::Find(Handle<Name> name,
 Handle<Code> PropertyICCompiler::ComputeMonomorphic(
     Code::Kind kind, Handle<Name> name, Handle<HeapType> type,
     Handle<Code> handler, ExtraICState extra_ic_state) {
-  CacheHolderFlag flag;
   Isolate* isolate = name->GetIsolate();
+  if (handler.is_identical_to(isolate->builtins()->LoadIC_Normal()) ||
+      handler.is_identical_to(isolate->builtins()->StoreIC_Normal())) {
+    name = isolate->factory()->normal_ic_symbol();
+  }
+
+  CacheHolderFlag flag;
   Handle<Map> stub_holder = IC::GetICCacheHolder(*type, isolate, &flag);
 
   Handle<Code> ic;