dillon1000/react

Revert "Remove old IE polyfill code" (#10483)

**what is the change?:**
This reverts https://github.com/facebook/react/commit/0b220d0f04c9fea472c7cf8a7837322388728ca6
Which was part of https://github.com/facebook/react/pull/10238

**why make this change?:**
When trying to sync the latest React with FB's codebase, we had failing
integration tests.

It looks like they are running with an old version of Chrome and there
is something related to file upload that fails when these polyfills are
missing.

For now we'd like to revert this to unblock syncing, but it's worth
revisiting this change to try and add some polyfill for FB and remove it
from React, or to fix whatever the specific issue was with our file
upload error.

**test plan:**
`yarn test` and also built and played with the `dom` and `packaging`
fixtures