[html-tests] Use the built-in harness timeout for failing relevant mutations tests ra... (#1769)

...ther than an artifically short one.

This test was rather unstable on our infrastructure, and this change is hoped to help with that.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/1769

Received on Tuesday, 21 April 2015 17:37:08 UTC