fs: add missing call to uv_fs_req_cleanup

Always call uv_fs_req_cleanup after calling uv_fs_open instead of just
when uv_fs_open returns a negative result. I referenced ReadFileSync
from node:js2c when making this change.

https://github.com/bnoordhuis made the same suggestion based on the
PR #49691.

Fixes: #57800
PR-URL: #57811
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: Justin-Nietzel

src/node_file.cc

@@ -2594,10 +2594,10 @@ static void ReadFileUtf8(const FunctionCallbackInfo<Value>& args) {
     FS_SYNC_TRACE_END(open);
     if (req.result < 0) {
       uv_fs_req_cleanup(&req);
-      // req will be cleaned up by scope leave.
       return env->ThrowUVException(
           static_cast<int>(req.result), "open", nullptr, path.out());
     }
+    uv_fs_req_cleanup(&req);
   }
 
   auto defer_close = OnScopeLeave([file, is_fd, &req]() {