src: fix -Winconsistent-missing-override warning

../src/node_http_common.h:497:8: warning: 'MemoryInfo' overrides a
member function but is not marked 'override' [-Winconsistent-missing-override]
  void MemoryInfo(MemoryTracker* tracker) const {

PR-URL: https://github.com/nodejs/node/pull/32126
Refs: https://github.com/nodejs/node/pull/32069


Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>