[es6] implement spread calls

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Because standalone V8 builds are not supported, assume this is part of a
 # Chromium build.
 import("//build/module_args/v8.gni")
 
 # TODO(jochen): These will need to be user-settable to support standalone V8
 # builds.
@@ skipping 219 matching lines @@
     "src/macros.py",
     "src/proxy.js",
     "src/generator.js",
     "src/harmony-string.js",
     "src/harmony-array.js",
     "src/harmony-array-includes.js",
     "src/harmony-typedarray.js",
     "src/harmony-tostring.js",
     "src/harmony-templates.js",
     "src/harmony-regexp.js",
+    "src/harmony-spread.js",
   ]
 
   outputs = [
     "$target_gen_dir/experimental-libraries.cc",
   ]
 
   args = [
            rebase_path("$target_gen_dir/experimental-libraries.cc",
                        root_build_dir),
            "EXPERIMENTAL",
@@ skipping 1304 matching lines @@
       sources += [
         "src/d8-debug.cc",
         "$target_gen_dir/d8-js.cc",
       ]
     }
     if (v8_enable_i18n_support) {
       deps += [ "//third_party/icu" ]
     }
   }
 }