8358617: java/net/HttpURLConnection/HttpURLConnectionExpectContinueTest.java fails with 403 due to system proxies

Backport-of: a377773fa76b46ac98533c61bc1410485390115e

Author: GoeLin

test/jdk/java/net/HttpURLConnection/HttpURLConnectionExpectContinueTest.java

@@ -429,7 +429,7 @@ private HttpURLConnection createConnection() throws Exception {
                 .port(control.serverSocket.getLocalPort())
                 .toURL();
 
-        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+        HttpURLConnection connection = (HttpURLConnection) url.openConnection(Proxy.NO_PROXY);
         connection.setDoOutput(true);
         connection.setReadTimeout(5000);
         connection.setUseCaches(false);