Test directory refactoring step 1.

Moving TestProjects and TestPackages under root 'TestAssets' folder.

Partial fix #1250

TestAssets/TestProjects/TestAppWithArgs/Program.cs

@@ -0,0 +1,18 @@
+using System;
+
+namespace ConsoleApplication
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            Console.WriteLine("Hello World!");
+
+            Console.WriteLine($"I was passed {args.Length} args:");
+            foreach (var arg in args)
+            {
+                Console.WriteLine($"arg: [{arg}]");
+            }
+        }
+    }
+}