net: optimize ipv6 check

Author: araujogui

lib/internal/socketaddress.js

@@ -158,7 +158,7 @@ class SocketAddress {
       // the raw input string instead.
       const { hostname: address } = URLParse(`http://${input}`);
 
-      const isIPv6 = address.startsWith('[') && address.endsWith(']');
+      const isIPv6 = address[0] === '[' && address.endsWith(']');
 
       // For IPv6, indexOf(']:') + 1 points at ':' (or 0 if absent, treated as no port).
       // For IPv4, lastIndexOf(':') points at ':' (or -1 if absent).