Cleans up the generator scripts to prepare for listing outputs in the generated hashes file. Also reorganizes the scripts somewhat to make them a bit more maintainable. Bug: angleproject:3227 Change-Id: If40946c2004941d3f6cd51d5521c7db8cc0b52df Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1512052Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>
