Get rid of WebInspector.TracingTimelineModel.Events.TracingComplete event

WebInspector.TimelineModel.Events.RecordingStopped is sufficient.

BUG=361045

Review URL: https://codereview.chromium.org/324683002

git-svn-id: svn://svn.chromium.org/blink/trunk@175796 bbb929c8-8fbe-4397-9dbb-9b2b20218538