Insert Microsoft.TestPlatform.cli for update3 preview1 (#6420)

* Fix test issue failing with PathTooLongIssue

(cherry picked from commit 340254f7742201c74ed1a5c349bdca89113bd5dc)

* fix for issues:
1) https://github.com/Microsoft/vstest/issues/755
2) https://github.com/Microsoft/vstest/issues/687
3) https://github.com/Microsoft/vstest/issues/737

(cherry picked from commit 0e93b2a5d4734637538781fa5401ed81a31eea0f)

* use new version

* Update version

* Fix pathtoolong issue

* Fix test

TestAssets/TestProjects/XunitMulti/UnitTest1.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;
+using Xunit;
+
+namespace TestNamespace
+{
+    public class VSTestXunitTests
+    {
+        [Fact]
+        public void VSTestXunitPassTest()
+        {
+        }
+
+        [Fact]
+        public void VSTestXunitFailTest()
+        {
+            Assert.Equal(1, 2);
+        }
+
+#if DESKTOP
+        [Fact]
+        public void VSTestXunitPassTestDesktop()
+        {
+        }
+#else
+        [Fact]
+        public void VSTestXunitFailTestNetCoreApp()
+        {
+            Assert.Equal(1, 2);
+        }
+#endif
+    }
+}