[ic] [stubs] Don't use Code::flags in megamorphic stub cache hash computations.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index ad7df3765f14a2f9334a5970b565a137242e395d..8217a287b48bd08f4f943e4c245ef981343ef899 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -17426,6 +17426,14 @@ Handle<UnseededNumberDictionary> UnseededNumberDictionary::AddNumberEntry(
   return Add(dictionary, key, value, PropertyDetails::Empty());
 }
 
+void UnseededNumberDictionary::DeleteKey(uint32_t key) {
+  int entry = FindEntry(key);
+  if (entry == kNotFound) return;
+
+  Factory* factory = GetIsolate()->factory();
+  SetEntry(entry, factory->the_hole_value(), factory->the_hole_value());
+  ElementRemoved();
+}
 
 Handle<SeededNumberDictionary> SeededNumberDictionary::AtNumberPut(
     Handle<SeededNumberDictionary> dictionary, uint32_t key,