Change the url in testDownloadWithDownloadManagerDisallowed

In China, "https://www.google.com" will redirect to url
"http://www.google.cn" but cleartext traffic is default disabled
for an app. So the testDownloadWithDownloadManagerDisallowed
would failed by cleartext traffic is not permitted. Thus, change
the url in the test which is reachable in China.

Bug: 192978910
Test: atest HostsideVpnTests#testDownloadWithDownloadManagerDisallowed
Original-Change: https://android-review.googlesource.com/1771008
Merged-In: I992c3240f0e133f5b00468cbe85d1545bcf786b0
Change-Id: I992c3240f0e133f5b00468cbe85d1545bcf786b0
diff --git a/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java b/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java
index 62aa493..215f129 100755
--- a/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java
+++ b/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java
@@ -1213,7 +1213,8 @@
                     new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
 
             // Enqueue a request and check only one download.
-            final long id = dm.enqueue(new Request(Uri.parse("https://www.google.com")));
+            final long id = dm.enqueue(new Request(
+                    Uri.parse("https://google-ipv6test.appspot.com/ip.js?fmt=text")));
             assertEquals(1, getTotalNumberDownloads(dm, new Query()));
             assertEquals(1, getTotalNumberDownloads(dm, new Query().setFilterById(id)));