Revert of Refactor avoidsFloats() to reflect CSS2.1 spec more clearly (https://codereview.chromium.org/268833003/)

Reason for revert:
Causing clusterfuzz crashes
BUG=388757

Original issue's description:
> Refactor avoidsFloats() to reflect CSS2.1 spec more clearly
> 
> Introduce the 'createsBlockFormatting' concept to RenderBlock::avoidsFloats()
> and remove a couple of now-redundant virtualizations of the function.
> 
> BUG=
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=173549
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=176557

Review URL: https://codereview.chromium.org/330913007

git-svn-id: svn://svn.chromium.org/blink/trunk@176943 bbb929c8-8fbe-4397-9dbb-9b2b20218538