Sync vs_toolschain.py up with Chromium.

win8sdk got renamed to win_sdk. Also minor fixes from upstream, mostly pylint.
Upstream also no longer keeps the toolchain hash in a separate file.

Change-Id: Iefc8bb6a487f0cdb13fcf3131b0fba317ca6548b
Reviewed-on: https://boringssl-review.googlesource.com/4982
Reviewed-by: Adam Langley <agl@google.com>
2 files changed