Add subset of Ubuntu18 jobs.

We currently have only one bot for these jobs, so we should treat them
as experimental for now.

Bug: 837351
Change-Id: I1ea9f1bf1635c36895eede80df6709509a85df90
Reviewed-on: https://skia-review.googlesource.com/c/168489
Commit-Queue: Ben Wagner <benjaminwagner@google.com>
Auto-Submit: Ben Wagner <benjaminwagner@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
4 files changed