Exit if we fail to load a JAR
Exit if we fail to load a JAR

Summary:
It's probably an error. At the very least it prevents reproducible
builds

Reviewed By: minjang

Differential Revision: D4703926

fbshipit-source-id: cc9e5a294a7bbeafb39fe992d676ecd903cfbba8

facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex,facebook/redex