autotest: do not print WiFi log messages using /usr/bin/logger on Android

Android does not have /usr/bin/logger available, so skip these when
running on an Android device.

Use isinstance(self.host, ADBHost) to detect that situation.
(That might not be ideal, but it is already in use in two other spots in
this source file.)

BUG=None.
TEST=Ran test_that command on adb host and it did not choke on logger.

Change-Id: I3f06cf3be44430407aa5fc46551abbf26eb35398
Signed-off-by: Filipe Brandenburger <filbranden@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/295688
Reviewed-by: mukesh agrawal <quiche@chromium.org>
2 files changed