tools: add eslint rule prefer-assert-methods

PR-URL: https://github.com/nodejs/node/pull/8622


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yorkie Liu <yorkiefixer@gmail.com>
Reviewed-By: Jackson Tian <shvyo1987@gmail.com>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>