Fetch API: Remove expectation files of request.js

Fixes the "duplicate test names" error for tests in request.js,
after which all test cases in request.js pass without warnings
or errors. So the expectation files can be safely removed.

BUG=624278

Review-Url: https://codereview.chromium.org/2778183002
Cr-Commit-Position: refs/heads/master@{#460257}
7 files changed