DevTools: split initial-modules-load test into per-panel tests

Chaining them all in one test does not make sense, as a module added
by one panel will show up in all dumps done after that.

Change-Id: If329f91bdf78d61338de7511e3669ede096b37e1
Reviewed-on: https://chromium-review.googlesource.com/565440
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485385}
13 files changed