Fuchsia: Fix deprecated jobs call

runtime/bin/process_fuchsia.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_FUCHSIA)
 
 #include "bin/process.h"
@@ skipping 718 matching lines @@
 
   mx_status_t SetupLaunchpad() {
     mx_handle_t binary_vmo = launchpad_vmo_from_file(path_);
     CHECK_FOR_ERROR(binary_vmo, "launchpad_vmo_from_file");
     binary_vmo_ = binary_vmo;
 
     launchpad_t* lp;
     mx_status_t status;
 
     mx_handle_t job = MX_HANDLE_INVALID;
-    status = mx_handle_duplicate(launchpad_get_mxio_job(), MX_RIGHT_SAME_RIGHTS,
-                                 &job);
+    status = mx_handle_duplicate(mx_job_default(), MX_RIGHT_SAME_RIGHTS, &job);
     CHECK_FOR_ERROR(status, "mx_handle_duplicate");
 
     status = launchpad_create(job, program_arguments_[0], &lp);
     CHECK_FOR_ERROR(status, "launchpad_create");
     launchpad_ = lp;
 
     status =
         launchpad_arguments(lp, program_arguments_count_, program_arguments_);
     CHECK_FOR_ERROR(status, "launchpad_arguments");
 
@@ skipping 93 matching lines @@
 void Process::ClearSignalHandler(intptr_t signal) {
   UNIMPLEMENTED();
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_FUCHSIA)
 
 #endif  // !defined(DART_IO_DISABLED)