FIx intellisense cache not refreshing (#831)

* FIx intellisense cache not refreshing

* Remove extra newlines

* Output label to provide more useful information in case of error

test/Microsoft.SqlTools.ServiceLayer.Test.Common/TestEventContext.cs

@@ -0,0 +1,19 @@
+using System.Threading.Tasks;
+using Microsoft.SqlTools.Hosting.Protocol;
+using Microsoft.SqlTools.Hosting.Protocol.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.Test.Common
+{
+    /// <summary>
+    /// Simple EventContext for testing that just swallows all events.
+    /// </summary>
+    public class TestEventContext : EventContext
+    {
+        public override async Task SendEvent<TParams>(
+            EventType<TParams> eventType,
+            TParams eventParams)
+        {
+            await Task.FromResult(0);
+        }
+    }
+}