Revert of [runtime] Introduce dedicated JSBoundFunction to represent bound functions.

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index 5ef7c0d91013fd01ba5f869437d26f264a6d436b..afa05bd125a6af0c94bf2ad39a7b7d2e8b8794df 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -477,11 +477,6 @@
   Handle<JSIteratorResult> NewJSIteratorResult(Handle<Object> value,
                                                Handle<Object> done);
 
-  // Allocates a bound function.
-  MaybeHandle<JSBoundFunction> NewJSBoundFunction(
-      Handle<JSReceiver> target_function, Handle<Object> bound_this,
-      Vector<Handle<Object>> bound_args);
-
   // Allocates a Harmony proxy.
   Handle<JSProxy> NewJSProxy(Handle<JSReceiver> target,
                              Handle<JSReceiver> handler);