clarify http version test (dotnet#44379)

Co-authored-by: Geoffrey Kizer <[email protected]>

src/libraries/Common/tests/System/Net/Http/HttpProtocolTests.cs

@@ -78,7 +78,7 @@ public async Task GetAsync_RequestVersion0X_ThrowsNotSupportedException(int mino
 
             using (HttpClient client = CreateHttpClient())
             {
-                HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, "http://bing.com");
+                HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, "http://nosuchhost.invalid");
                 request.Version = new Version(0, minorVersion);
 
                 Task<HttpResponseMessage> getResponseTask = client.SendAsync(TestAsync, request);