Revert of Add the ability to build Chrome tools to the Win Clang build script. (patch...

Revert of Add the ability to build Chrome tools to the Win Clang build script. (patchset #2 id:20001 of https://codereview.chromium.org/1068603002/)

Reason for revert:
Broke all bots on http://build.chromium.org/p/chromium.fyi/console?category=win%20clang , they fail with:

________ running 'C:\b\depot_tools\python276_bin\python.exe src/tools/clang/scripts/update.py --if-needed' in 'C:\b\build\slave\CrWinClang\build'
usage: update.py [-h] [--no-clobber] [--tools [TOOLS [TOOLS ...]]]
update.py: error: unrecognized arguments: --if-needed

Probably easy to fix (just add a dummy --if-needed parameter to argparse), but reverting to get that waterfall back to green.

Original issue's description:
> Add the ability to build Chrome tools to the Win Clang build script.
>
> BUG=424436,467287
>
> Committed: https://crrev.com/475949d9430b6a759ce759f2133dd3a1577d0d0b
> Cr-Commit-Position: refs/heads/master@{#324089}

TBR=hans@chromium.org,dcheng@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=424436,467287

Review URL: https://codereview.chromium.org/1063273002

Cr-Commit-Position: refs/heads/master@{#324138}