Remove a slow line of code that was only for ie9
Remove a slow line of code that was only for ie9

refs: CORE-3020

This line causes a forced “Recalculate Style” which takes my fast
macbookPro 5ms in prod. Since it’s only for ie9, we can remove it

Change-Id: I8ccdc8301c45edc2e49426b3203a8c3e5102c8e7
Reviewed-on: https://gerrit.instructure.com/195703
Tested-by: Jenkins
Reviewed-by: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>
QA-Review: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>
Product-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>

sfu/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms