Modal (form) buttons no longer support two lines

What I expected to happen was...:
Modals buttons correctly show both lines of text on them.
 
What actually happened was...:
Modal buttons show the first line, then three dots, and don't render the second line at all.
 
Steps to Reproduce:
1. Create a modal, of the form type, and add a button that has two lines of text, split with a newline (\n)
2. View the modal.
 
Alternatively:
1. Join Featured Server The Hive
2. Right click with the Compass, view the modal.
 
Screenshots of old (1.7) and new (1.8) are included.