test: removed unused variable in fs-watch-file-slow

PR-URL: #23548
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Gireesh Punathil <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>

Author: makitoda

Diff for: test/pummel/test-fs-watch-file-slow.js

@@ -34,7 +34,7 @@ let nevents = 0;
 
 try {
   fs.unlinkSync(FILENAME);
-} catch (e) {
+} catch {
   // swallow
 }