lib: remove an unused variable

PR-URL: #23482
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

Author: chenyil

lib/internal/bootstrap/node.js

@@ -504,7 +504,9 @@
           const { kExpandStackSymbol } = NativeModule.require('internal/util');
           if (typeof er[kExpandStackSymbol] === 'function')
             er[kExpandStackSymbol]();
-        } catch (er) {}
+        } catch {
+          // Nothing to be done about it at this point.
+        }
         return false;
       }