Fix P2P migration

Fixes #4269 by deep cloning the MsbuildTemplateProject for each P2P reference. Add test which migrates and builds P2P references.

TestAssets/TestProjects/TestAppDependencyGraph/ProjectF/Helper.cs

@@ -1,15 +0,0 @@
-// 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;
-
-namespace TestLibrary
-{
-    public static class ProjectE
-    {
-        public static string GetMessage()
-        {
-            return "This string came from ProjectF";
-        }
-    }
-}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectF/Program.cs

@@ -0,0 +1,19 @@
+// 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.Diagnostics;
+
+namespace TestApp
+{
+    public class Program
+    {
+        public static int Main(string[] args)
+        {
+            Console.WriteLine("This string came from ProjectF");
+            string helperStr = TestLibrary.ProjectG.GetMessage();
+            Console.WriteLine(helperStr);
+            return 0;
+        }
+    }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectF/project.json

@@ -1,22 +1,20 @@
 {
   "version": "1.0.0-*",
   "buildOptions": {
-    "nowarn": [
-      "CS1591"
-    ],
-    "xmlDoc": true,
-    "additionalArguments": [
-      "-highentropyva+"
-    ]
+    "emitEntryPoint": true,
+    "preserveCompilationContext": true
   },
   "dependencies": {
     "ProjectG": {
       "target": "project",
       "version": "1.0.0-*"
     },
-    "NETStandard.Library": "1.6.0"
+    "Microsoft.NETCore.App": {
+      "type": "platform",
+      "version": "1.0.1"
+    }
   },
   "frameworks": {
-    "netstandard1.5": {}
+    "netcoreapp1.0": {}
   }
 }