Attach light children after removing a shadow root.

Attach light children after removing a shadow root.
https://bugs.webkit.org/show_bug.cgi?id=74267

Reviewed by Ryosuke Niwa.

Source/WebCore:

Tests: fast/dom/shadow/dynamically-created-shadow-root-expected.html
       fast/dom/shadow/dynamically-created-shadow-root.html:

* dom/Element.cpp:
(WebCore::Element::removeShadowRoot):

LayoutTests:

* fast/dom/shadow/dynamically-created-shadow-root-expected.html:
* fast/dom/shadow/dynamically-created-shadow-root.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@106336 268f45cc-cd09-0410-ab3c-d52691b4dbfc