8349551: Failures in tests after JDK-8345625

Reviewed-by: jpai, dfuchs

src/java.net.http/share/classes/jdk/internal/net/http/HttpClientImpl.java

@@ -1636,6 +1636,11 @@ final class HttpClientImpl extends HttpClient implements Trackable {
         return Optional.ofNullable(userProxySelector);
     }
 
+    // Return the effective proxy that this client uses.
+    ProxySelector proxySelector() {
+        return proxySelector;
+    }
+
     @Override
     public WebSocket.Builder newWebSocketBuilder() {
         // Make sure to pass the HttpClientFacade to the WebSocket builder.