deps: patch V8 to 6.4.388.42

PR-URL: https://github.com/nodejs/node/pull/18578
Refs: https://github.com/v8/v8/compare/6.4.388.41...6.4.388.42


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>