All logging should be done via ERR() and WARN(),
which call angle::Platform's logError and logWarning,
if there is current Platform which supports logging.
Otherwise, ERR() is directed to std::cerr.

Misc fixes to keep tests passing.

BUG=angleproject:1660, angleproject:1644

Change-Id: I2bca33a021537185d0c236a3083789af3236b5f3
Reviewed-on: https://chromium-review.googlesource.com/434188
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>