[infra] Make CheckGeneratedFiles use Clang

Bug: skia:9675
Change-Id: Ie9fcd38a4d6c1e369bb2c3740de664a87d1a322c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/256660
Reviewed-by: Herb Derby <herb@google.com>
Reviewed-by: Ben Wagner aka dogben <benjaminwagner@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
7 files changed