Bugs fixes so XEvent profiler isn't broken (#577)

* Fix a few issues with profiler method handlers

* Filter out profiler polling events

* Add a unit test for profiler events

* Add method comment headers

src/Microsoft.SqlTools.ServiceLayer/Profiler/Contracts/StopProfilingRequest.cs

@@ -13,7 +13,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Profiler.Contracts
     /// </summary>
     public class StopProfilingParams
     {
-        public string SessionId { get; set; }
+        public string OwnerUri { get; set; }
     }
 
     public class StopProfilingResult