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

base/base_unittests.isolate

 # Copyright (c) 2012 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.
 {
   'variables': {
     'command': [
       '../testing/test_env.py',
       '<(PRODUCT_DIR)/base_unittests<(EXECUTABLE_SUFFIX)',
       '--brave-new-test-launcher',
       '--test-launcher-bot-mode',
       '--asan=<(asan)',
       '--msan=<(msan)',
       '--tsan=<(tsan)',
     ],
   },
   'conditions': [
     ['OS=="android" or OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
         'files': [
           'test/data/',
         ],
       },
     }],
     ['OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
         'files': [
           '../testing/test_env.py',
           '<(PRODUCT_DIR)/base_unittests<(EXECUTABLE_SUFFIX)',
         ],
-        'read_only': 1,
       },
     }],
     ['OS=="linux"', {
       'variables': {
         'files': [
           '<(PRODUCT_DIR)/lib/libmalloc_wrapper.so',
         ],
       },
     }],
     ['OS=="mac" and asan==1 and fastbuild==0', {
       'variables': {
         'files': [
           '<(PRODUCT_DIR)/base_unittests.dSYM/',
         ],
       },
     }],
     ['OS=="win" and (fastbuild==0 or fastbuild==1)', {
       'variables': {
         'files': [
           '<(PRODUCT_DIR)/base_unittests.exe.pdb',
         ],
       },
     }],
   ],
   'includes': [
     'base.isolate',
   ],
 }