Use ComputeHandlerFlags to find handlers, rather than manually encoding.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 9ecbe6a157c560f15ec91d1ae1a14e50aecd0574..7360172e5b5d6a1036cd5af55e016b2dbb8a6567 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -7511,9 +7511,11 @@ MaybeObject* CodeCache::UpdateNormalTypeCache(Name* name, Code* code) {
 
 
 Object* CodeCache::Lookup(Name* name, Code::Flags flags) {
-  flags = Code::RemoveTypeFromFlags(flags);
-  Object* result = LookupDefaultCache(name, flags);
-  if (result->IsCode()) return result;
+  Object* result = LookupDefaultCache(name, Code::RemoveTypeFromFlags(flags));
+  if (result->IsCode()) {
+    if (Code::cast(result)->flags() == flags) return result;
+    return GetHeap()->undefined_value();
+  }
   return LookupNormalTypeCache(name, flags);
 }