Attempt to fix bind tests for non-en-US

While it's definitly intended for `@bind` to have culture-sensitive
output for most cases, we want the tests to behave consistently for all
developers.

So this is an attempt to use a fixed culture for all of our testing.

src/Components/test/testassets/BasicTestApp/Program.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Globalization;
 using Microsoft.AspNetCore.Blazor.Hosting;
 
 namespace BasicTestApp
@@ -9,6 +10,9 @@ namespace BasicTestApp
     {
         public static void Main(string[] args)
         {
+            // We want the culture to be en-US so that the tests for bind can work consistently.
+            CultureInfo.CurrentCulture = new CultureInfo("en-US");
+
             CreateHostBuilder(args).Build().Run();
         }
 

src/Components/test/testassets/TestServer/Startup.cs

@@ -5,6 +5,7 @@ using Microsoft.AspNetCore.Authentication.Cookies;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Localization;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
@@ -76,7 +77,12 @@ namespace TestServer
                     options.AddSupportedCultures("en-US", "fr-FR");
                     options.AddSupportedUICultures("en-US", "fr-FR");
 
-                    // Cookie culture provider is included by default.
+                    // Cookie culture provider is included by default, but we want it to be the only one.
+                    options.RequestCultureProviders.Clear();
+                    options.RequestCultureProviders.Add(new CookieRequestCultureProvider());
+
+                    // We want the default to be en-US so that the tests for bind can work consistently.
+                    options.SetDefaultCulture("en-US"); 
                 });
 
                 app.UseRouting();