test: Shorten the ValidatorSite request timeout case

The timeout case waited for the 12s request timeout every other case
uses as headroom for slow DNS, plus the server's 13s sleep, twice per
run. testFetchList() now takes the request timeout as a parameter, and
the timeout case uses 1s against a 2s server sleep, which keeps the
1s gap between the two. The suite drops from about 35s to about 13.5s.

src/test/app/ValidatorSite_test.cpp

@@ -132,8 +132,21 @@ private:
         std::chrono::seconds effectiveOverlap = detail::kDefaultEffectiveOverlap;
         int expectedRefreshMin = 0;
     };
+
+    /**
+     * Serve each configured list from its own publisher server, fetch them all
+     * through one ValidatorSite and check what it reports for each site.
+     *
+     * @param good Directory the cache files are written to.
+     * @param paths One server per entry, with what to serve and what to expect.
+     * @param requestTimeout How long the ValidatorSite waits for a response
+     * before it reports that the request took too long.
+     */
     void
-    testFetchList(detail::DirGuard const& good, std::vector<FetchListConfig> const& paths)
+    testFetchList(
+        detail::DirGuard const& good,
+        std::vector<FetchListConfig> const& paths,
+        std::chrono::seconds requestTimeout = std::chrono::seconds{12})
     {
         testcase << "Fetch list - "
                  << boost::algorithm::join(
@@ -211,10 +224,10 @@ private:
 
         BEAST_EXPECT(trustedKeys.load({}, emptyCfgKeys, cfgPublishers));
 
-        // Normally, tests will only need a fraction of this time,
-        // but sometimes DNS resolution takes an inordinate amount
-        // of time, so the test will just wait.
-        auto sites = std::make_unique<ValidatorSite>(env.app(), journal, 12s);
+        // Normally, tests will only need a fraction of the default timeout,
+        // but sometimes DNS resolution takes an inordinate amount of time, so
+        // the test will just wait.
+        auto sites = std::make_unique<ValidatorSite>(env.app(), journal, requestTimeout);
 
         std::vector<std::string> uris;
         for (auto const& u : servers)
@@ -586,18 +599,19 @@ public:
                         .failApply = true,
                     },
                 });
-            // timeout
+            // timeout: the server answers 1s after the request times out
             testFetchList(
                 good,
                 {
                     {
-                        .path = "/sleep/13",
+                        .path = "/sleep/2",
                         .msg = "took too long",
                         .ssl = ssl,
                         .failFetch = true,
                         .failApply = true,
                     },
-                });
+                },
+                std::chrono::seconds{1});
             // bad manifest format using known versions
             // * Retrieves a v1 formatted list claiming version 2
             testFetchList(