End after the second ping in longPolling custom query string test

- Previously the longPolling transport would ping after its test was complete
  causing subsequent runs of the same test for other transports to fail.
Make HubGroupFacts.js pass with simultaneous runs.

- By making the group name "random", it is a lot less likely that multiple
  browsers running the tests in HubGroupFacts.js simultaneously will cause
  issues.
Calling DemoHub.DoSomethingAndCallError while AjaxSendFacts.js

is being run no longer causes tests to fail.
Handle connection.start.fail in test.utilities.js

- output reason for failure