AMP Runtime: allow usage of iterator/destructure/spread/rest

## Description

Awhile back we decided to start allowing for iterator to be used (https://github.com/ampproject/amphtml/pull/34249). The logic was that it only adds 0.12kb to any bundle which uses it, and only `.js` builds as opposed to `.mjs` builds. We started implementation of this change, but ran into roadblocks (https://github.com/ampproject/amphtml/pull/34282#pullrequestreview-657290325)

### To do:

Update these plugins/rules to handle `ArrayExpression`:
- [x] build-system/eslint-rules/no-deep-destructuring.js: https://github.com/ampproject/amphtml/pull/35698
- [ ] build-system/eslint-rules/unused-private-field.js
- [ ] [Descoped] ~build-system/eslint-rules/prefer-destructuring.js~

Can be removed:
- [x] build-system/babel-plugins/babel-plugin-transform-simple-array-destructure/index.js (https://github.com/ampproject/amphtml/pull/35695)
- [x] no-array-destructuring, no-rest, no-spread (https://github.com/ampproject/amphtml/pull/35699)

cc @ampproject/wg-performance

Start with build-system/eslint-rules/unused-private-field.js and compare its handling of ArrayExpression with the completed no-deep-destructuring.js change linked in the issue. Review the related Babel and rule-removal pull requests for context, then verify that the remaining rule handles ArrayExpression without breaking its existing checks.

Written by the indexing model from the issue text.