Fix Clang dEQP build on Win. Rolls the build/ repos from Chromium to include the fixed config. Also includes incidental improvements to platform-specific hooks. Bug: chromium:727437 Change-Id: Ia42a30acac1e800e593e304bfc59d86eb0a1e57c Reviewed-on: https://chromium-review.googlesource.com/782340 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>