Remove RenderElement::s_affectsParentBlock

Remove RenderElement::s_affectsParentBlock
https://bugs.webkit.org/show_bug.cgi?id=183187
<rdar://problem/37961079>

Reviewed by Antti Koivisto.

Remove the hack to track floating/out-of-flow changes between styleWillChange and styleDidChange.

Covered by existing tests.

* rendering/RenderElement.cpp:
(WebCore::RenderElement::styleWillChange):
(WebCore::RenderElement::styleDidChange):
* rendering/RenderElement.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@229091 268f45cc-cd09-0410-ab3c-d52691b4dbfc