dillon1000/react

chore(syntheticEvent): remove IE8 code (#11178)

* chore(syntheticEvent): remove IE8 code

Since IE8 has been deprecated for a while, I thought it might be useful to remove some IE8-only code

If this is not something you want to focus on yet, or is too much work to test, feel free to close this PR

* Update SyntheticUIEvent.js

* Update SyntheticUIEvent.js

* remove unused require

* completely remove UIEvent

* augment with noop

everything breaks otherwise

* comment back

* spacing