Work around build test.sln race condition until fixed (#5490)

* Remove GenerateRuntimeConfigurationFiles from this library

* Disable parallel build of test.sln

* PR feedback

build_projects/dotnet-cli-build/DotNetMSBuildTool.cs

@@ -0,0 +1,32 @@
+// 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 Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+
+using Microsoft.DotNet.Cli.Build.Framework;
+
+namespace Microsoft.DotNet.Cli.Build
+{
+    public abstract class DotNetMSBuildTool : DotNetTool
+    {
+        public int MaxCpuCount {get; set;} = 0;
+
+        protected override string Args 
+        { 
+            get
+            {
+                return $"{GetMaxCpuCountArg()}";
+            } 
+        }
+
+        private string GetMaxCpuCountArg()
+        {
+            if (MaxCpuCount > 0)
+            {
+                return $"/m:{MaxCpuCount}";
+            }
+
+            return null;
+        }
+    }
+}