The often used construct {OFStream(stdout)} does not work on Android.
This CL introduces an {StdoutStream} which behaves exactly like
{OFStream(stdout)} on non-android platforms, and redirects to the
Android log on appropriate systems and configurations.

R=mstarzinger@chromium.org

Bug: v8:7820
Change-Id: Ia682fdf6d064e37c605c19b032f5a10b96ac825b
Reviewed-on: https://chromium-review.googlesource.com/1088911Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53692}