This is a reland of 0909dbe3.
Added missing V8_EXPORT_PRIVATE to AndroidLogStream.

TBR=mstarzinger@chromium.org

Original change's description:
> Introduce StdoutStream which prints to Android log or stdout
>
> 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/1088911
> Reviewed-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}

Bug: v8:7820
Change-Id: I8164bad78a401dbe4246c9ffcacd050fe511ed58
Reviewed-on: https://chromium-review.googlesource.com/1100636Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53733}