fix slice alias crash after same document navigation

The WPT tests navigation-api/navigation-methods/navigate-history-push-same-url.html
crashed with a @memcpy arguments alias error.

It seems to be due to the reuse of the previous page.url string.
Forcing to duplicate it fixes the crash.

src/browser/webapi/navigation/Navigation.zig

@@ -271,9 +271,16 @@ pub fn navigateInner(
     const committed = local.createPromiseResolver();
     const finished = local.createPromiseResolver();
 
-    const new_url = try URL.resolve(arena, page.url, url, .{});
+    var new_url = try URL.resolve(arena, page.url, url, .{});
     const is_same_document = URL.eqlDocument(new_url, page.url);
 
+    // In case of navigation to the same document, we force an url duplication.
+    // Keeping the same url generates a crash during WPT test navigate-history-push-same-url.html.
+    // When building a script's src, script's base and page url overlap.
+    if (is_same_document) {
+        new_url = try arena.dupeZ(u8, new_url);
+    }
+
     const previous = self.getCurrentEntry();
 
     switch (kind) {