Move the CLI corefx dependencies from RC2 to RC3 - rc3-24113-00.

- Disable crossgen for windows.Tracked by - https://github.com/dotnet/cli/issues/3059
- And also fix #2974

TestAssets/TestProjects/DependencyContextValidator/DependencyContextValidator/project.json

@@ -6,7 +6,7 @@
     }
   },
   "frameworks": {
-    "netstandard1.5": {
+    "netstandard1.6": {
       "imports": "dnxcore50",
       "dependencies": {
         "Microsoft.NETCore.App": "1.0.0-rc3-*"