Query Execution: Better exception handling on unawaited async tasks (#502)

* WIP

* This code makes it work!

* Adding similar exception hanling behavior to saving result sets

* Adding unit tests for new extension methods
Auto-cleanup of proj file whitespace

* Implementing changes as per code review comments

test/Microsoft.SqlTools.ServiceLayer.UnitTests/Utility/TaskExtensionTests.cs

@@ -0,0 +1,53 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Threading.Tasks;
+using Microsoft.SqlTools.ServiceLayer.Utility;
+using Xunit;
+
+namespace Microsoft.SqlTools.ServiceLayer.UnitTests.Utility
+{
+    public class TaskExtensionTests
+    {
+        [Fact]
+        public async Task ContinueWithOnFaultedNullContinuation()
+        {
+            // Setup: Create a task that will definitely fault
+            Task failureTask = new Task(() => throw new Exception("It fail!"));
+            
+            // If: I continue on fault and start the task
+            Task continuationTask = failureTask.ContinueWithOnFaulted(null);
+            failureTask.Start();
+            await continuationTask;
+
+            // Then: The task should have completed without fault
+            Assert.Equal(TaskStatus.RanToCompletion, continuationTask.Status);
+        }
+
+        [Fact]
+        public async Task ContinueWithOnFaultedContinuatation()
+        {
+            // Setup: 
+            // ... Create a new task that will definitely fault
+            Task failureTask = new Task(() => throw new Exception("It fail!"));
+            
+            // ... Create a quick continuation task that will signify if it's been called
+            Task providedTask = null;
+
+            // If: I continue on fault, with a continuation task
+            Task continuationTask = failureTask.ContinueWithOnFaulted(task => { providedTask = task; });
+            failureTask.Start();
+            await continuationTask;
+            
+            // Then:
+            // ... The task should have completed without fault
+            Assert.Equal(TaskStatus.RanToCompletion, continuationTask.Status);
+            
+            // ... The continuation action should have been called with the original failure task
+            Assert.Equal(failureTask, providedTask);
+        }
+    }
+}