Revert of mac: Roll hermetic toolchain to Xcode 8.3.2.

Revert of mac: Roll hermetic toolchain to Xcode 8.3.2. (patchset #5 id:80001 of https://codereview.chromium.org/2941293003/ )

Reason for revert:
gclient runhooks failing on 4 builders:

WebKit Mac10.11
WebKit Mac10.11 (dbg)
WebKit Mac10.11 (retina)
WebKit Mac10.9

Findit (?) suspects CL abd9ba0 with 70% confidence.

e.g. stdout:
https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Fchromium.webkit%2FWebKit_Mac10.11%2F20904%2F%2B%2Frecipes%2Fsteps%2Fgclient_runhooks%2F0%2Fstdout

npacking new toolchain.
Accepting license.
Executable requires at least macOS 10.12, but is being run on macOS 10.11.3, and so is exiting.Failed to download toolchain toolchain-8E2002-3.tgz.
Exception Command '['sudo', '/usr/bin/xcodebuild', '-license', 'accept']' returned non-zero exit status 134
Exiting.
Error: Command '/usr/bin/python src/build/mac_toolchain.py' returned non-zero exit status 1 in /b/c/b/mac_layout



Original issue's description:
> mac: Roll hermetic toolchain to Xcode 8.3.2.
> 
> Xcode 8.3.2 requires macOS 10.12+. This version of Xcode 8.3.2 has both the
> 10.10 and 10.12 SDKs, and builds will continue to use the 10.10 SDK.
> 
> BUG=624049
> 
> Review-Url: https://codereview.chromium.org/2941293003
> Cr-Commit-Position: refs/heads/master@{#480685}
> Committed: https://chromium.googlesource.com/chromium/src/+/abd9ba0ebfca0ce7a37c14593d55ebee56c4a55c

TBR=dpranke@chromium.org,erikchen@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=624049

[hayato, 2017-06-20 03:37:18]

The CQ bit was checked by hayato@chromium.org

[hayato, 2017-06-20 03:37:18]

Created Revert of mac: Roll hermetic toolchain to Xcode 8.3.2.

[commit-bot: I haz the power, 2017-06-20 03:37:43]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-06-20 03:38:02]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-06-20 03:38:05]

Failed to apply the patch.
On branch working_branch
Your branch is up-to-date with 'origin/refs/heads/master'.
nothing to commit, working tree clean

[hayato, 2017-06-20 03:51:41]

Looks the CL was already reverted at https://codereview.chromium.org/2949743002/
Closing.