Simplify the thunk targets since we don't support apps as components

examples/apptest/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/mojo_application.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 
 group("apptest") {
   testonly = true
 
   deps = [
     ":apptests",
     ":service",
   ]
 }
 
 mojo_native_application("service") {
   output_name = "example_service"
 
   sources = [
     "example_service_application.cc",
     "example_service_application.h",
     "example_service_impl.cc",
     "example_service_impl.h",
   ]
 
   deps = [
     ":bindings",
-    "//mojo/public/c/system:for_shared_library",
     "//mojo/public/cpp/application:standalone",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/system",
     "//mojo/public/cpp/utility",
   ]
 }
 
 mojo_native_application("apptests") {
   output_name = "example_apptests"
 
   testonly = true
 
   sources = [
     "example_apptest.cc",
     "example_client_impl.cc",
     "example_client_impl.h",
   ]
 
    deps = [
     ":bindings",
-    "//mojo/public/c/system:for_shared_library",
     "//mojo/public/cpp/application:standalone",
     "//mojo/public/cpp/application:test_support_standalone",
     "//mojo/public/cpp/bindings:callback",
     "//mojo/public/cpp/environment",
     "//mojo/public/cpp/system",
    ]
 
    datadeps = [ ":service", ]
 }
 
 mojom("bindings") {
   sources = [ "example_service.mojom" ]
 }