JNLPManagerTest fails due to failure of embedded JNLP tests.

Moreover it seem to leave some threads alive after itself and this will cause preloader test failures later. (i can reproduce jnlpmanagertest failure runing test alone but not preloader). The root reason seem that embedded content is missing in the cache? and there qill be attempt to download it from fake location.
There seems to be some interference from some other unit tests. I ran JNLPManagerTest by itself it passed. The downloading from fake location would have get unresolved host exception and result in null launch descriptor so the test should pass, but for efficiency, we need to use local file URL so the download failure happen instantly.