Add browser test and testing config for dynamic Expect-CT reporting

This CL adds a browser test to check that the ChromeExpectCTReporter is properly
created and set up to receive reports, particularly for dynamic Expect-CT
violations. It also enables the dynamic Expect-CT feature on the waterfall.

BUG=679012,642517

Change-Id: I3ea01207ea5852b9bd0bbb1d90799ee4555c854e
Reviewed-on: https://chromium-review.googlesource.com/566572
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Reviewed-by: Mustafa Emre Acer <meacer@chromium.org>
Commit-Queue: Emily Stark <estark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#486158}
3 files changed