Use testharness.js instead of js-test.js in fast/images.

This test used testharness.js instead of js-test.js
in server-side-imagemap and webgl-teximage2d.

BUG=637859

Review-Url: https://codereview.chromium.org/2253513005
Cr-Commit-Position: refs/heads/master@{#412532}
4 files changed