feat: use a global symbol for `util.promisify.custom`#44

ExE-Boss wants to merge 1 commit intobrowserify:masterbrowserify/node-util:masterfrom

EB-Forks:feat/use-global-util-promisify-custom-symbolEB-Forks/node-util:feat/use-global-util-promisify-custom-symbolCopy head branch name to clipboard