Remove unused function from InspectorAgent.

Remove 'inspectedURLWithoutFragment()' from InspectorAgent as it's never called.

Review URL: https://codereview.chromium.org/98433002

git-svn-id: svn://svn.chromium.org/blink/trunk@162968 bbb929c8-8fbe-4397-9dbb-9b2b20218538