Fix flakiness of FTP PAC tests.

Use 0.0.0.1:1 in place of 0.0.0.0:8000 as the address of the proxy server.

The test expects connections to the proxy server to fail - however connecting
to the ANY address (0.0.0.0) can succeed.

The new literal should fail consistently since:
  (1) 0.0.0.1 is a reserved IP address.
  (2) We disallow connections on TCP port 1.

Bug: 996367
Change-Id: I54ce278e75983110961da0cc49dd923decdd5ae2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1765662Reviewed-by: Matt Menke <mmenke@chromium.org>
Commit-Queue: Eric Roman <eroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689615}

chrome/browser/net/network_context_configuration_browsertest.cc

@@ -1729,9 +1729,7 @@ class NetworkContextConfigurationFtpPacBrowserTest
   DISALLOW_COPY_AND_ASSIGN(NetworkContextConfigurationFtpPacBrowserTest);
 };
 
-// Flaky: crbug.com/996367
-IN_PROC_BROWSER_TEST_P(NetworkContextConfigurationFtpPacBrowserTest,
-                       DISABLED_FtpPac) {
+IN_PROC_BROWSER_TEST_P(NetworkContextConfigurationFtpPacBrowserTest, FtpPac) {
   if (IsRestartStateWithInProcessNetworkService())
     return;
   std::unique_ptr<network::ResourceRequest> request =

chrome/test/data/bad_server.pac

-function FindProxyForURL(url, host){ return "PROXY 0.0.0.0:8000;"; }
+function FindProxyForURL(url, host){ return "PROXY 0.0.0.1:1;"; }