Delete network inspector test for SharedWorker.

We are moving the worker script loading code to the shared worker process.
http://crbug.com/329786
After this cl (https://codereview.chromium.org/133093003/), the loading task is executed in the worker process.

See https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/p1FMy9f8DL8 for more details.

BUG=329786

Review URL: https://codereview.chromium.org/150573008

git-svn-id: svn://svn.chromium.org/blink/trunk@167174 bbb929c8-8fbe-4397-9dbb-9b2b20218538