Fix product bug causing Httplistener test failures

Author: hughbe

src/System.Net.HttpListener/src/System/Net/Windows/HttpListener.Windows.cs

@@ -1628,7 +1628,7 @@ private ArrayList BuildChallenge(AuthenticationSchemes authenticationScheme, ulo
 
             if ((authenticationScheme & AuthenticationSchemes.Basic) != 0)
             {
-                AddChallenge(ref challenges, "Basic realm =\"" + Realm + "\"");
+                AddChallenge(ref challenges, "Basic realm=\"" + Realm + "\"");
             }
 
             return challenges;

src/System.Net.HttpListener/tests/AuthenticationTests.cs

@@ -71,7 +71,7 @@ public async Task BasicAuthentication_InvalidRequest_SendsStatusCodeClient(strin
 
                 if (statusCode == HttpStatusCode.Unauthorized)
                 {
-                    Assert.Equal("Basic realm =\"\"", response.Headers.WwwAuthenticate.ToString());
+                    Assert.Equal("Basic realm=\"\"", response.Headers.WwwAuthenticate.ToString());
                 }
                 else
                 {
@@ -103,7 +103,7 @@ public async Task BasicAuthentication_RealmSet_SendsChallengeToClient(string rea
             using (var client = new HttpClient())
             {
                 HttpResponseMessage response = await AuthenticationFailure(client, HttpStatusCode.Unauthorized);
-                Assert.Equal($"Basic realm =\"{realm}\"", response.Headers.WwwAuthenticate.ToString());
+                Assert.Equal($"Basic realm=\"{realm}\"", response.Headers.WwwAuthenticate.ToString());
             }
         }