Remove Mojo bindings environment.

mojo/edk/js/tests/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.
 
 import("../../../../mojo/public/tools/bindings/mojom.gni")
 
 source_set("js_to_cpp_tests") {
   testonly = true
 
   deps = [
@@ skipping 12 matching lines @@
     "js_to_cpp_tests.cc",
   ]
 
   configs += [ "//v8:external_startup_data" ]
 }
 
 mojom("js_to_cpp_bindings") {
   sources = [
     "js_to_cpp.mojom",
   ]
-
-  with_environment = false
 }