Twenty Sixteen: Remove IE specific checks #9999

Job	Run time
Core running from build / Core running from build / Linux	2m 1s
Core running from src / Core running from src / Linux	1m 58s
Core running from build / Core running from build / Windows	3m 48s
Core running from src / Core running from src / Windows	3m 29s
Core running from build / Core running from build / MacOS	1m 44s
Core running from src / Core running from src / MacOS	2m 41s
Gutenberg running from build / Gutenberg running from build / Linux	8m 46s
Gutenberg running from src / Gutenberg running from src / Linux	10m 8s
Gutenberg running from build / Gutenberg running from build / Windows	11m 52s
Gutenberg running from src / Gutenberg running from src / Windows	12m 2s
Gutenberg running from build / Gutenberg running from build / MacOS	7m 56s
Gutenberg running from src / Gutenberg running from src / MacOS	8m 0s
Slack Notifications	0s
Failed workflow tasks	0s
	1h 14m 25s

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