add clang-tools-extra to clang_linux

This should get us clang-tidy, among other tools.

Change-Id: If58aa059eea025b46e43a3178f25a90120678c2c
Reviewed-on: https://skia-review.googlesource.com/c/176972
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
3 files changed