test(http): replay one fallback route table over both listeners

The point of the feature is that a URL means the same thing over either
protocol, so the test states it that way: one route map plus one
fallback, registered with ListenerHTTP1 and ListenerHTTP, asked the same
eight questions, asserting identical answers.

Covers exact routes beating the fallback, query strings still routing to
the bare path, the fallback seeing the full target including the query,
the fallback choosing its own status (404 and 303), a throwing fallback
becoming a 500, and an unset fallback still producing the listener's own
synthetic 404.

Verified against a broken build both ways: dropping the fallback lookup
fails 9 checks, dropping the query-strip fails 2.

project.cpp

@@ -119,6 +119,7 @@ extern "C" Configuration CrafterBuildProject(std::span<const std::string_view> a
     // crafter-network static lib via .Dependencies({ &cfg }).
     if (cfg.target == "x86_64-pc-linux-gnu") {
         cfg.AddTest("ShouldEchoWebTransport").Dependencies({ &cfg });
+        cfg.AddTest("ShouldFallbackUnknownRoutes").Dependencies({ &cfg });
         cfg.AddTest("ShouldInteropCurlHTTP1").Dependencies({ &cfg });
         cfg.AddTest("ShouldNotDropEarlyStreams").Dependencies({ &cfg });
         cfg.AddTest("ShouldParseHTTP1").Dependencies({ &cfg });