luci: specify core counts for chromium.clang builders.

Bug: 964674
Change-Id: Ib243128c333c2a685706834340198ca3ed3a600d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1617695
Commit-Queue: John Budorick <jbudorick@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661196}
1 file changed