Devtools: re-enable editor ctrl-D test

This test is now no longer flaky/failing locally on my machine. I'm
attempting to re-enable in the CI system.

Bug: 849284

Change-Id: I74809701307005ac90d047627b72e66b0abb19b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2605395


Reviewed-by: Robert Paveza <Rob.Paveza@microsoft.com>
Commit-Queue: Brandon Goddard <brgoddar@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#839495}