- added inspector test suite definition in testcfg.py
- added JS infrastructure for tests in protocol-test.js

BUG=chromium:635948
R=dgozman@chromium.org,alph@chromium.org

Committed: https://crrev.com/4a5f5d0991656a6aa45b0021a0f5ba6a7ceabe15
Review-Url: https://codereview.chromium.org/2370743003
Cr-Original-Commit-Position: refs/heads/master@{#39895}
Cr-Commit-Position: refs/heads/master@{#39930}