Add missing copyright headers to all cs files

test/Microsoft.DotNet.Tools.Tests.Utilities/Extensions/ProcessExtensions.cs

@@ -1,3 +1,6 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -117,8 +120,8 @@ namespace Microsoft.DotNet.Tools.Test.Utilities
             var taskCompletionSource = new TaskCompletionSource<object>();
 
             subject.EnableRaisingEvents = true;
-            
-            subject.Exited += (s, a) => 
+
+            subject.Exited += (s, a) =>
             {
                 taskCompletionSource.SetResult(null);