REGRESSION(r160182): Fragment parser doesn't close a form element with a close tag

REGRESSION(r160182): Fragment parser doesn't close a form element with a close tag
https://bugs.webkit.org/show_bug.cgi?id=139561

Reviewed by Darin Adler.

Source/WebCore:

The bug was caused by us not setting the form pointer in insertHTMLFormElement.
Since we already avoid associating a form inside HTMLConstructionSite::createHTMLElement,
we didn't need this code at all.

Fixed the bug by partially reverting r160182.

Test: fast/dom/dom-parse-close-form.html

* html/parser/HTMLConstructionSite.cpp:
(WebCore::HTMLConstructionSite::insertHTMLFormElement):
(WebCore::HTMLConstructionSite::insideTemplateElement): Deleted.
* html/parser/HTMLConstructionSite.h:

LayoutTests:

Added a regression test.

* fast/dom/dom-parse-close-form-expected.txt: Added.
* fast/dom/dom-parse-close-form.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@177263 268f45cc-cd09-0410-ab3c-d52691b4dbfc