DevTools: re-use new test runner modules in legacy test helpers (part 1)

This eliminates a lot of the code duplication between the new and legacy
integration test frameworks by making the legacy test helper files small
wrappers to load the new *test_runner modules.

* syntax-highlight.js - no longer needed because it's in TestRunner.js
* Line numbers changed in indexed DB tests because inspected page helper
functions are executed in anonymous scripts with initAsync

Drive-by: This also removes unused files in http/tests/inspector
that are no longer needed now that the tests have all been moved to
http/tests/devtools.

Bug: 667560
Change-Id: Ifc6655dbf76d9b56d6e6de0fff3103a533cf6e31
Reviewed-on: https://chromium-review.googlesource.com/719711
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Will Chen <chenwilliam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508931}
66 files changed