Build Cleanup: Part 2 (#3890)

* Remove deprecated build_projects sources

* Remove BuildSetup, StandardGoals, and Target Attributes

* Incremental restore of tasks dll

* CheckPreReq conforms with MSBuild Error Handling guidelines

* Eliminate deprecated content

* PR Feedback

build_projects/shared-build-targets-utils/BuildFailureException.cs

@@ -0,0 +1,19 @@
+using System;
+
+namespace Microsoft.DotNet.Cli.Build
+{
+    public class BuildFailureException : Exception
+    {
+        public BuildFailureException()
+        {
+        }
+
+        public BuildFailureException(string message) : base(message)
+        {
+        }
+        
+        public BuildFailureException(string message, Exception innerException) : base(message, innerException)
+        {
+        }
+    }
+}