Make serialization scriptingEnabled-dependent

[domenic]

https://html.spec.whatwg.org/#serialising-html-fragments says

If the parent of current node is a style, script, xmp, iframe, noembed, noframes, or plaintext element, or if the parent of current node is a noscript element and scripting is enabled for the node, then append the value of current node's data IDL attribute literally.

parse5 does not seem to implement this additional condition, and doesn't seem to even have the ability to tell the serializer about scripting-enabled or not:

parse5/packages/parse5/lib/serializer/index.js

Lines 136 to 149 in 9c683e1

	if (
	parentTn === $.STYLE ||
	parentTn === $.SCRIPT ||
	parentTn === $.XMP ||
	parentTn === $.IFRAME ||
	parentTn === $.NOEMBED ||
	parentTn === $.NOFRAMES ||
	parentTn === $.PLAINTEXT ||
	parentTn === $.NOSCRIPT
	) {
	this.html += content;
	} else {
	this.html += Serializer.escapeString(content, false);
	}

This is causing this web platform test to fail in jsdom.