lib: remove unnecessary symbols

Remove `(...)`, because this is a simple,sensitive expression.

PR-URL: #22455
Reviewed-By: Weijia Wang <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Gus Caplan <[email protected]>
Reviewed-By: Tiancheng "Timothy" Gu <[email protected]>
Reviewed-By: Tobias Nießen <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: James M Snell <[email protected]>

lib/_stream_readable.js

@@ -147,7 +147,7 @@ function Readable(options) {
 
   // Checking for a Stream.Duplex instance is faster here instead of inside
   // the ReadableState constructor, at least with V8 6.5
-  const isDuplex = (this instanceof Stream.Duplex);
+  const isDuplex = this instanceof Stream.Duplex;
 
   this._readableState = new ReadableState(options, this, isDuplex);