Revert of Remove chromeos==0 blacklist for test_isolation_mode.

Revert of Remove chromeos==0 blacklist for test_isolation_mode. (patchset #2 id:20001 of https://codereview.chromium.org/1214903013/)

Reason for revert:
fails 'compile on ChromiumOS x86-generic Compile, Link:

https://build.chromium.org/p/chromium.chromiumos/builders/ChromiumOS%20x86-generic%20Compile/builds/1797

Error like
[6346/6381] RULE interactive_ui_tests_run:
isolate_66259a49d84685497c67f134062c657d interactive_ui_tests.isolate
/* snip */
FAILED: cd ../../chrome; python ../tools/isolate_driver.py check --isolated
"../out_x86-generic/Release/interactive_ui_tests.isolated" --isolate
"interactive_ui_tests.isolate" /* snip */
Failed to find an input file: Input file
/b/build/slave/ChromiumOS_x86-generic_Compile/build/src/out_x86-generic/Release/nacl_irt_x86_64.nexe doesn't exist

Original issue's description:
> Remove chromeos==0 blacklist for test_isolation_mode.
>
> All of plain linux, chromeos work just fine and have been for a long time.
>
> iOS and Android are also using .isolate files but in a different enough way that
> it's not using test_isolation_mode==check, at least not yet.
>
> TBR=smut@chromium.org
> BUG=98637
>
> Committed: https://crrev.com/cf15207e009794f74915d9b10d2e838b0d0c86f2
> Cr-Commit-Position: refs/heads/master@{#337503}

TBR=smut@chromium.org,smut@google.com,maruel@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=98637
Committed: https://crrev.com/f7c5ec7bcc7fd73d7927fad9bca9bd82c6f6e793
Cr-Commit-Position: refs/heads/master@{#337533}

[tapted, 2015-07-07 00:30:07]

Created Revert of Remove chromeos==0 blacklist for test_isolation_mode.

[commit-bot: I haz the power, 2015-07-07 00:31:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1227583002/1

[smut, 2015-07-07 00:35:34]

lgtm

[commit-bot: I haz the power, 2015-07-07 00:35:57]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-07 00:37:09]

Patchset 1 (id:??) landed as
https://crrev.com/f7c5ec7bcc7fd73d7927fad9bca9bd82c6f6e793
Cr-Commit-Position: refs/heads/master@{#337533}