Remove 'read_only': 1 from most .isolate files.

net/net_unittests.isolate

 # 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.
 {
   'conditions': [
     ['OS=="android" or OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
         'files': [
           'data/',
         ],
@@ skipping 12 matching lines @@
         ],
         'files': [
           '../testing/test_env.py',
           '../third_party/pyftpdlib/',
           '../third_party/pywebsocket/',
           '../third_party/tlslite/',
           '<(PRODUCT_DIR)/net_unittests<(EXECUTABLE_SUFFIX)',
           '<(PRODUCT_DIR)/pyproto/google/',
           'tools/testserver/',
         ],
-        'read_only': 1,
       },
     }],
     ['OS=="mac" and asan==1 and fastbuild==0', {
       'variables': {
         'files': [
           '<(PRODUCT_DIR)/net_unittests.dSYM/',
         ],
       },
     }],
     ['OS=="win" and (fastbuild==0 or fastbuild==1)', {
       'variables': {
         'files': [
           '<(PRODUCT_DIR)/net_unittests.exe.pdb',
         ],
       },
     }],
   ],
   'includes': [
     '../base/base.isolate',
     '../gin/v8.isolate',
   ],
 }