Fix a potential segfault on log message for failing to load module

Using the `call_arena` here is unsafe in the case of a failure. It's possible
for the call_arena to be reset during module processing, making the log crash.

The issue is that the lifetime of a URL is often conditional. If the stitched
URL has already been seen (i.e. is in the module_cache), then it can be short-
lived. EXCEPT, URL.stitch might require an allocation..and then you start to
think, well, if URL.stitch is going to allocate anyways...If we stitch with
the `page.arena`, and end up not needing a long lifetime, we've wasted memory.
If we stitch with `page.call_arena` and end up needing a long lifetime, we need
to dupe.

It's a bit messy, and I'd like to take a stab at improving it after:
https://github.com/lightpanda-io/browser/pull/1127.

I'm thinking that we need a URL intern pool. HashMap with a composite key of
base + path -> resolved. Then all URLs are resolved using the page.arena, but
we don't have any duplicates, so it isn't wasteful.

src/browser/js/Context.zig

@@ -1171,7 +1171,7 @@ fn _resolveModuleCallback(self: *Context, referrer: v8.Module, specifier: []cons
     };
 
     const normalized_specifier = try self.script_manager.?.resolveSpecifier(
-        self.call_arena,
+        self.arena, // might need to survive until the module is loaded
         specifier,
         referrer_path,
     );