Add flow typing to environment-jsdom (#1158)
Add flow typing to environment-jsdom (#1158)

TSIA.
sampepose/jest,bookman25/jest,ide/jest,Daniel15/jest,blainekasten/jest,bookman25/jest,skovhus/jest,mpontus/jest,skovhus/jest,blainekasten/jest,skovhus/jest,cpojer/jest,facebook/jest,ide/jest,cpojer/jest,cpojer/jest,sampepose/jest,Daniel15/jest,aaron-goshine/jest,ide/jest,facebook/jest,bookman25/jest,aaron-goshine/jest,mpontus/jest,blainekasten/jest,Daniel15/jest,mpontus/jest,facebook/jest,aaron-goshine/jest