Revert 283610 "Revert 283562 "Mojo: Enable mojo_shell_tests on W..."

Should be okay now, according to my local testing (see crbug.com/389666,
etc.; crrev.com/285139 also fixed a use-after-free that would be picked
up by this test on Debug builds).

> Revert 283562 "Mojo: Enable mojo_shell_tests on Windows (on the ..."
>
> Blech: Stuff fails. Shockingly.
> http://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%284%29/builds/27268/steps/mojo_shell_tests/logs/stdio
>
> > Mojo: Enable mojo_shell_tests on Windows (on the bots).
> >
> > R=sky@chromium.org
> >
> > Review URL: https://codereview.chromium.org/398023002
>
> TBR=viettrungluu@chromium.org
>
> Review URL: https://codereview.chromium.org/398253002

TBR=viettrungluu@chromium.org, sky@chromium.org

Review URL: https://codereview.chromium.org/413263002

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@285430 4ff67af0-8c30-449e-8e8b-ad334ec8d88c