On a very large test suite (8000 specs), a significant amount
of time is spent just drawing the spec dots. Some sort of
worse-than-linear artifact that summons itself only when you
have 8000 floated elements trying to hang out together.
This performance penalty is not seen with inline-block.
In Chrome 29:
Floated dots: 16.795s
Inline-block dots: 2.774s
Setting the dots to 'display: none;' takes about the same time
as the inline-block figure, so this is probably a low enough bound
(no need for chunked rendering or who knows what).