Bug 1586358 - Replace existing instances of GENERATED_FILES with references to...

Bug 1586358 - Replace existing instances of GENERATED_FILES with references to the GeneratedFile template r=nalexander

This patch doesn't remove all references to GENERATED_FILES, but does remove most of them, leaving only those which can't be trivially translated to the new template.

Try push: https://treeherder.mozilla.org/#/jobs?repo=try&revision=e4a25230c3992b9c5519ceb351fb37f6b2bf605e

Differential Revision: https://phabricator.services.mozilla.com/D48230

--HG--
extra : moz-landing-system : lando