[annotation-protocol-tests] Clean whitespace from incoming URLs (#3963)

We received reports that tests were breaking due to at least a `container_url` being passed in with untrimmed white space (i.e. " http://..."). This fixes that.

/cc @halindrome @azaroth42 @iherman

View on GitHub: https://github.com/w3c/web-platform-tests/pull/3963

Received on Tuesday, 11 October 2016 18:58:44 UTC