Revert "Reland "git-cl: Execute clang-format-diff.py using vpython.""
Revert "Reland "git-cl: Execute clang-format-diff.py using vpython.""

This reverts commit 87661afbfc1b59fbfb64183379f2aadaac6c84c7.

Reason for revert: Still get:
OSError: Execution failed with error: [Error 2] The system cannot find the file specified.

Original change's description:
> Reland "git-cl: Execute clang-format-diff.py using vpython."
> 
> This is a reland of beec66070ea79d5cad14d27927ef1bb2f0f01793
> 
> Append the clang-format directory to the front of PATH instead of
> overwriting it.
> This allows vpython to be invoked.
> 
> Original change's description:
> > git-cl: Execute clang-format-diff.py using vpython.
> >
> > When running git-cl using vpython3, sys.executable is python3.
> > Execute clang-format-diff.py using vpython instead, since it has
> > not been migrated already.
> >
> > Bug: 1066187
> > Change-Id: I31556acb50ff4256706a313c1393eddad9f903f3
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2130926
> > Reviewed-by: Josip Sokcevic <sokcevic@google.com>
> > Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
> 
> Bug: 1066187
> Change-Id: I8b65549ef47587cef8492f8f76a037eb85a981fc
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2132972
> Reviewed-by: Josip Sokcevic <sokcevic@google.com>
> Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

TBR=ehmaldonado@chromium.org,apolito@google.com,infra-scoped@luci-project-accounts.iam.gserviceaccount.com,sokcevic@google.com

Change-Id: I22566c829a83991e3749a039d0bd0ba7d8a56812
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1066187
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2133588
Reviewed-by: John Budorick <17d38a2d68c6a07a3ab0ce4a2873c5acefbd3dbb@chromium.org>
Commit-Queue: John Budorick <17d38a2d68c6a07a3ab0ce4a2873c5acefbd3dbb@chromium.org>

CoherentLabs/depot_tools,CoherentLabs/depot_tools