Add Ubuntu18 Calmbench and Valgrind jobs

Change-Id: Ie12013d2a337727d4a170863be7b124ef8d36ad6
Reviewed-on: https://skia-review.googlesource.com/c/191741
Auto-Submit: Ben Wagner <benjaminwagner@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
Reviewed-by: Eric Boren <borenet@google.com>