Sort file lists in artifacts.json

[cknitt]

scripts/prepublish.js is (as far as I understand) meant to be run in the local working copy before publishing to npm.

It

• runs npm pack --dry-run to get the list of files that would be published
• transforms the list into a JSON structure (why?)
• writes that structure to jscomp/artifacts.json and
• diffs that file against what's currently committed in the (remote) repo.

This way the person doing npm publishing can see if all expected files are there (e.g., binaries for the different platforms) and if there are any new or removed files since the last publish.

I ran the script on my Mac and got a huge amount of changes, because the files were returned in a different sort order than in the current artifacts.json.

I have therefore sorted the current artifacts.json manually (actually with a small helper script) and also changed prepublish.js to sort the files. Now when I run prepublish.js again, I get an actually usable and useful diff of "current" vs. "expected".

[cristianoc]

Good catch.