- Make testcfg.py ignore files ending in "_FIXTURE.js", which are not supposed
  to be tested standalone but only as imports to other modules.

- Refine test262.status to match where we are with the modules implementation.

BUG=v8:1569
R=adamk@chromium.org

Review-Url: https://codereview.chromium.org/2400713004
Cr-Commit-Position: refs/heads/master@{#40134}