repl: remove unused variable from try catch

Catch statement defines err variable that is never used, so it
is safe to remove that.

PR-URL: #23452
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

lib/internal/repl/await.js

@@ -69,7 +69,7 @@ function processTopLevelAwait(src) {
  let root;
  try {
  root = acorn.parse(wrapped, { ecmaVersion: 10 });
- } catch (err) {
+ } catch {
  return null;
  }
  const body = root.body[0].expression.callee.body;