[Swarming] Speed up test262 upload/download.

test/test262/test262.gyp

 # Copyright 2015 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'conditions': [
     ['test_isolation_mode != "noop"', {
       'targets': [
         {
           'target_name': 'test262_run',
           'type': 'none',
           'dependencies': [
             '../../src/d8.gyp:d8_run',
           ],
           'includes': [
             '../../build/features.gypi',
             '../../build/isolate.gypi',
           ],
           'sources': [
             'test262.isolate',
           ],
+          'actions': [
+            {
+              'action_name': 'archive_test262',
+              'inputs': ['archive.py', '<!@(python list.py)'],
+              'outputs': ['data.tar'],
+              'action': ['python', 'archive.py'],
+            },
+          ],
         },
       ],
     }],
   ],
 }