[Perf] Simplify Template.Perf Program.cs (Azure#19124)

Author: mikeharder

sdk/template/Azure.Template/perf/Program.cs

@@ -1,16 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-using System.Threading.Tasks;
+using System.Reflection;
 using Azure.Test.Perf;
 
-namespace Azure.Template.Perf
-{
-    public class Program
-    {
-        public static async Task Main(string[] args)
-        {
-            await PerfProgram.Main(typeof(Program).Assembly, args);
-        }
-    }
-}
+ await PerfProgram.Main(Assembly.GetEntryAssembly(), args);