Summary of the changes:
* expand `node_smoke_tests` to test the full & slim builds
* run `compare_size` on all built minified files; don't run it anymore on
unminified files where they don't provide lots of value
The main goal of this change is to make it easier to compare sizes of both the
full & slim builds between the `3.x-stable` & `main` branches.
Closes gh-5291
Ref gh-5255
(partially cherry-picked from commit 8be4c0e4f8)
While we have absolutely no style-related expectations to our minified file,
we do care that it's valid ES 5.1. This is now verified.
Also, update grunt-eslint as a newer ESLint version is required to be able
to use "extends" inside of the "overrides" section.
Fixes gh-3075
Closes gh-4594
Ref gh-4598
So far, we've been testing that jQuery element iteration works with polyfilled
Symbol & transpiled for-of via a Node test with jsdom with the Symbol global
removed. Unfortunately, jsdom now requires Symbol to be present for its internal
functionality so such a test is no longer possible. Instead, it's been migrated
to an iframe test with transpiled JavaScript.
This PR also enables us to use ECMAScript 2017 or newer in Node.js code.
Closes gh-4305
