Fix for JERSEY-2223 and similar issue in server-async example test.

- Server async & connector timeout unit tests updated.
  - Minor changes in unit tests in attempt to resolve intermittent Hudson build failures caused mainly by newly added Jetty connector tests and async example tests.

Change-Id: I94848a895a674d0f93133b4e4c5f9398baf8d687
Signed-off-by: Marek Potociar <marek.potociar@oracle.com>