PRs to port from the main Babel repository

[nicolo-ribaudo]

These PRs might already be working in this repo, but we need to check.

• Don't allow instance properties transformation on namespace babel#10372 Don't allow instance properties transformation on namespace Don't allow instance properties transformation on namespace #5
• Inject core-js@3 imports in Program:exit instead of on post() babel#10146 Inject core-js@3 imports in Program:exit instead of on post() (they are now imported when visiting the node which needs them)
• feat(transform-runtime): add more type hints for instance methods babel#10068 feat(transform-runtime): add more type hints for instance methods (probably not the whole PR since it adds many unnecessary hints, but we need to check if I forgot some of them)
• Replace es.string.reverse with es.array.reverse babel#10284 Replace es.string.reverse with es.array.reverse
• resolve #10205 babel#10207 a variable named 'filter' can be incorrectly transformed by transform-runtime plugin

Issues:

• https://github.com/babel/babel/issues/ (3f3e551)