Honor the setting for whether JavaScript markup is enabled
https://bugs.webkit.org/show_bug.cgi?id=113122

Reviewed by Ryosuke Niwa.

Source/WebCore: 

* dom/ScriptableDocumentParser.cpp:
(WebCore::ScriptableDocumentParser::ScriptableDocumentParser): Applied the
setting here, so all document parsing would be covered. This is similar
to what we do for plug-in stripping.

* html/parser/HTMLConstructionSite.cpp:
(WebCore::HTMLConstructionSite::insertForeignElement): Fixed a bug where
we would insert an SVG script element into the document even in script
markup disabled mode.

(This bug has existed for copy/paste for a long time, but other bugs and
quirks in SVG copy/paste papered over it. It's a serious issue now
that non-paste clients will rely on this mode.)

* html/parser/HTMLTreeBuilder.cpp:
(WebCore::HTMLTreeBuilder::processTokenInForeignContent): Fixed the same
bug -- this time in the part of the parser that executes scripts as they
parse.

I adopted the toScriptElement() convention for testing for a script
element to match the XML parser.

LayoutTests: 

* editing/unsupported-content/script-markup-enabled-setting-expected.txt: Added.
* editing/unsupported-content/script-markup-enabled-setting.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147018 268f45cc-cd09-0410-ab3c-d52691b4dbfc