[IC] Also use LoadNonexistentDH for keyed loads

Unlike the old manually written LoadNonexistent stub, the data handler properly supports keyed loads out of the box. Simply remove the condition that disables it.

BUG=

Review-Url: https://codereview.chromium.org/2693913002
Cr-Commit-Position: refs/heads/master@{#43165}

src/ic/ic.cc

@@ -1130,12 +1130,8 @@ void LoadIC::UpdateCaches(LookupIterator* lookup) {
       lookup->state() == LookupIterator::ACCESS_CHECK) {
     code = slow_stub();
   } else if (!lookup->IsFound()) {
-    if (IsLoadIC() || IsLoadGlobalIC()) {
-      TRACE_HANDLER_STATS(isolate(), LoadIC_LoadNonexistentDH);
-      code = LoadNonExistent(receiver_map(), lookup->name());
-    } else {
-      code = slow_stub();
-    }
+    TRACE_HANDLER_STATS(isolate(), LoadIC_LoadNonexistentDH);
+    code = LoadNonExistent(receiver_map(), lookup->name());
   } else {
     if (IsLoadGlobalIC() && lookup->state() == LookupIterator::DATA &&
         lookup->GetReceiver().is_identical_to(lookup->GetHolder<Object>())) {