Revert of Isolate nacl_loader_unittests (https://codereview.chromium.org/322333006/)

Reason for revert:
This is causing the following error when running gyp_chromium with disable_nacl=1:

Traceback (most recent call last):
  File "./build/gyp_chromium", line 314, in <module>
    gyp_rc = gyp.main(args)
  File "/chromium/src/tools/gyp/pylib/gyp/__init__.py", line 527, in main
    return gyp_main(args)
  File "/chromium/src/tools/gyp/pylib/gyp/__init__.py", line 503, in gyp_main
    options.circular_check)
  File "/chromium/src/tools/gyp/pylib/gyp/__init__.py", line 129, in Load
    params['parallel'], params['root_targets'])
  File "/chromium/src/tools/gyp/pylib/gyp/input.py", line 2759, in Load
    RemoveLinkDependenciesFromNoneTargets(targets)
  File "/chromium/src/tools/gyp/pylib/gyp/input.py", line 1483, in RemoveLinkDependenciesFromNoneTargets
    if targets[t].get('variables', {}).get('link_dependency', 0):
KeyError: '/chromium/src/components/nacl.gyp:nacl_loader_unittests#target'


Original issue's description:
> Isolate nacl_loader_unittests
> 
> Isolate the Linux-only nacl_loader_unittests.
> 
> BUG=384515
> TBR=maruel
> NOTRY=true
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=278620

TBR=vadimsh@chromium.org,mseaborn@chromium.org,maruel@chromium.org,jln@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=384515

Review URL: https://codereview.chromium.org/348803004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278643 0039d316-1c4b-4281-b951-d872f2087c98

components/nacl.gyp

@@ -447,24 +447,6 @@
         }],
       ],
     }],
-    ['test_isolation_mode != "noop"', {
-      'targets': [
-        {
-          'target_name': 'nacl_loader_unittests_run',
-          'type': 'none',
-          'dependencies': [
-            'nacl_loader_unittests',
-          ],
-          'includes': [
-            '../build/isolate.gypi',
-            'nacl_loader_unittests.isolate',
-          ],
-          'sources': [
-            'nacl_loader_unittests.isolate',
-          ],
-        },
-      ],
-    }],
   ],
   'targets': [
     {

components/nacl_loader_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=="linux"', {
-      'variables': {
-        'command': [
-          '<(PRODUCT_DIR)/nacl_loader_unittests',
-        ],
-        'isolate_dependency_tracked': [
-          '<(PRODUCT_DIR)/nacl_loader_unittests',
-        ],
-        'read_only': 1,
-      },
-    }],
-  ],
-  'includes': [
-    '../sandbox/sandbox_linux_unittests.isolate',
-  ],
-}