fix(fs): instanceof check for Deno.FsFile (#22121)

Regression caused by https://github.com/denoland/deno/pull/22072.

I added a relevant test so we don't regress again.

Fixes https://github.com/denoland/deno/issues/22115

1 files changed, 5 insertions, 2 deletions

diff --git a/ext/node/polyfills/_fs/_fs_fsync.ts b/ext/node/polyfills/_fs/_fs_fsync.ts
index 942aecf6a..75d4b3756 100644
--- a/ext/node/polyfills/_fs/_fs_fsync.ts
+++ b/ext/node/polyfills/_fs/_fs_fsync.ts
@@ -10,9 +10,12 @@ export function fsync(
   fd: number,
   callback: CallbackWithError,
 ) {
-  new FsFile(fd).sync().then(() => callback(null), callback);
+  new FsFile(fd, Symbol.for("Deno.internal.FsFile")).sync().then(
+    () => callback(null),
+    callback,
+  );
 }
 
 export function fsyncSync(fd: number) {
-  new FsFile(fd).syncSync();
+  new FsFile(fd, Symbol.for("Deno.internal.FsFile")).syncSync();
 }