Removing Microsoft.DotNet.TestFramework from the product code and from the SDK deployment and moving the code to the test folder.

test/Microsoft.DotNet.TestFramework/Extensions/DirectoryInfoExtensions.cs

@@ -0,0 +1,35 @@
+// 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.IO;
+
+namespace Microsoft.DotNet.TestFramework
+{
+    internal static class DirectoryInfoExtensions
+    {
+        public static bool Contains(this DirectoryInfo subject, FileSystemInfo target)
+        {
+            return target.FullName.StartsWith(subject.FullName);
+        }
+
+        public static DirectoryInfo GetDirectory(this DirectoryInfo subject, params string [] directoryNames)
+        {
+            return new DirectoryInfo(Path.Combine(subject.FullName, Path.Combine(directoryNames)));
+        }
+
+        public static FileInfo GetFile(this DirectoryInfo subject, string fileName)
+        {
+            return new FileInfo(Path.Combine(subject.FullName, fileName));
+        }
+
+        public static void EnsureExistsAndEmpty(this DirectoryInfo subject)
+        {
+            if (subject.Exists)
+            {
+                subject.Delete(true);
+            }
+
+            subject.Create();
+        }
+    }
+}