Summary:
This fixes the case where we change the layout, so that it doesn't overflow anymore.
This also improves the readability by using `|=` instead of referencing the value twice.
Closes https://github.com/facebook/yoga/pull/587
Differential Revision: D5388657
Pulled By: emilsjolander
fbshipit-source-id: ce1b1ded1feed7314a2c16bf695f62b866c19ea0