[test-infra] Need clean or hide the area of dump result json after clicking start button again (#1006)

we check the dump json result,and start test. The dump json area show in the bottom of the page .but we when restart the test ,the dump json area does not hide or clear.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/1006

Received on Friday, 23 May 2014 03:33:18 UTC