replace `chunk.hasRuntime` with `chunk.parents.length === 0`
replace `chunk.hasRuntime` with `chunk.parents.length === 0`

see https://github.com/webpack/webpack/pull/4310\#discussion_r102400692

rlugojr/webpack,NekR/webpack,webpack/webpack,rlugojr/webpack,webpack/webpack,jescalan/webpack,SimenB/webpack,g0ddish/webpack,ts-webpack/webpack,jescalan/webpack,EliteScientist/webpack,SimenB/webpack,NekR/webpack,g0ddish/webpack,ts-webpack/webpack,rlugojr/webpack,SimenB/webpack,webpack/webpack,webpack/webpack,g0ddish/webpack,jescalan/webpack,ts-webpack/webpack,SimenB/webpack,ts-webpack/webpack,EliteScientist/webpack