trick Chrome's prescanner into not downloading ie11 polyfill
trick Chrome's prescanner into not downloading ie11 polyfill

chrome's prescanner tries to be smart and finds
any "document.write"s and preemptively downloads them
ahead of time so they load faster. this is to trick
it into not recognizing it and downloading it since
it won't need it.

test plan:
* load a page in chrome
* you should not see a request for vendor/ie11-polyfill
* load a page in IE11
* in the deveoloper tools in IE11, do:
 Promise.resolve().then(function(){console.log('it works')})
* it should log "it works"

Change-Id: Ic664a41f636121207667bdd989c7fc0d455ed172
Reviewed-on: https://gerrit.instructure.com/94501
Tested-by: Jenkins
Reviewed-by: Clay Diffrient <9dff2e5c98626d20d2848250c411e8009465bb87@instructure.com>
QA-Review: Benjamin Christian Nelson <4a283f6b032925e40a485c88ede5597d7d65a090@instructure.com>
Product-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>

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