Revert "Roll buildtools and enable in-tree libc++ on Android"

This reverts commit 1a874fe60ccb87401867a7334b8eb11e5e4b1552.

Reason for revert:
This broke the build, see bug.

Original change's description:
> Roll buildtools and enable in-tree libc++ on Android
> 
> Buildtools changelog:
> https://chromium.googlesource.com/chromium/buildtools/+log/7d88270de197ebe8b439ab5eb57a4a2a0bb810e0..0e1cbc4eab6861b0c84bf2ed9a3c4b7aa2063819
> 
> BUG=767901
> R=​thakis
> 
> Change-Id: I96fdafca5e228cbfe7a0909170c0235e7845bbde
> Reviewed-on: https://chromium-review.googlesource.com/c/1385021
> Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
> Commit-Queue: Nico Weber <thakis@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Reviewed-by: Dirk Pranke <dpranke@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#618035}

TBR=thakis@chromium.org,dpranke@chromium.org,thomasanderson@chromium.org

Change-Id: Ia54846c3ad7ed2fd03cb3c52bd1d0c18a1461a91
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 767901,916962
Reviewed-on: https://chromium-review.googlesource.com/c/1386434
Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618194}
2 files changed