[Tests] In the dotnet tests, if using vb force the lang to latest instead of the 'preview' used by the sdk.

tests/common/DotNet.cs

@@ -176,6 +176,10 @@ namespace Xamarin.Tests {
 				// Work around https://github.com/dotnet/msbuild/issues/8845
 				args.Add ("/v:diag");
 				args.Add ("/consoleloggerparameters:Verbosity=Quiet");
+				args.Add ("/consoleloggerparameters:Verbosity=Quiet");
+				// vb does not have preview lang, so we force it to latest
+				if (project.EndsWith (".vbproj", StringComparison.OrdinalIgnoreCase))
+					args.Add ("/p:LangVersion=latest");
 				// End workaround
 
 				var env = new Dictionary<string, string?> ();