Rename android_tools to android_sdk

Build-only change, land after: https://crrev.com/c/1543468

Bug: chromium:947060
Change-Id: I99fa3491e7aee96d6fb8f96cf9fa2dbf767180f4
Reviewed-on: https://webrtc-review.googlesource.com/c/deps/third_party/openmax/+/130262
Reviewed-by: Nico Weber <thakis@chromium.org>