Update Istanbul to 0.4.x
Update Istanbul to 0.4.x

Summary:
They have a shiny new report style that's quite nice and there are some bugfixes included. No breaking changes.

https://github.com/gotwarlost/istanbul/blob/master/CHANGELOG.md
Closes https://github.com/facebook/jest/pull/656

Reviewed By: svcscm

Differential Revision: D2802913

fb-gh-sync-id: 240dc225318d39a0b540c4d928a426feabcd7543

razh/jest,sampepose/jest,bookman25/jest,bookman25/jest,ide/jest,cpojer/jest,skawian/jest,Daniel15/jest,skovhus/jest,mpontus/jest,razh/jest,blainekasten/jest,ide/jest,ncuillery/jest,yungsters/jest,cpojer/jest,aaron-goshine/jest,mpontus/jest,blainekasten/jest,aaron-goshine/jest,skawian/jest,cpojer/jest,yungsters/jest,aaron-goshine/jest,skovhus/jest,ncuillery/jest,Daniel15/jest,bookman25/jest,facebook/jest,ide/jest,Daniel15/jest,alvinsj/jest,facebook/jest,mpontus/jest,facebook/jest,alvinsj/jest,sampepose/jest,skovhus/jest,blainekasten/jest