Re: [infra-tests] use context manager instead of prerun script (#5771)

These tests are now available on [w3c-test.org](https://w3c-test.org/submissions/5771/)

View on GitHub: https://github.com/w3c/web-platform-tests/pull/5771#issuecomment-298947148

Received on Wednesday, 3 May 2017 15:31:17 UTC