linux: Build clang-format in a sysroot

The binary shouldn't depend on what system it was built on.
We already have a sysroot for chromium, so just use that.

Built at the same revision as previously (eb85e90350e).
No expected behavior change.

Bug: none
Change-Id: Iddced88221bd8864c5a33963ca7796b0660d0732
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2790525
Auto-Submit: Nico Weber <thakis@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Reviewed-by: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#867197}
GitOrigin-RevId: f49c3c2b22187975d2b46c0c7785b1ec44d7ce54
1 file changed