[api] Use shallow copy for the template instantiation cache

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 32e3fa16dfd4312dccfba783d0addc872de94c5e..81175619bb764c360a132ab38d694ecff25dbfb8 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2380,10 +2380,6 @@ class JSObject: public JSReceiver {
       Handle<JSObject> object,
       AllocationSiteUsageContext* site_context,
       DeepCopyHints hints = kNoHints);
-  // Deep copies given object with special handling for JSFunctions which
-  // 1) must be Api functions and 2) are not copied but left as is.
-  MUST_USE_RESULT static MaybeHandle<JSObject> DeepCopyApiBoilerplate(
-      Handle<JSObject> object);
   MUST_USE_RESULT static MaybeHandle<JSObject> DeepWalk(
       Handle<JSObject> object,
       AllocationSiteCreationContext* site_context);