[WebKit] Browsermark DomAdvSearch and DomSearch optimizations

        This patch is a combination of the following optimizations.

        Optimize appendCharactersReplacingEntities

        [Performance] Optimize innerHTML and outerHTML
        https://bugs.webkit.org/show_bug.cgi?id=81214

        Optimize Dromaeo/dom-query.html by caching NodeRareData on Document
        https://bugs.webkit.org/show_bug.cgi?id=90059

        Optimize Dromaeo/dom-attr.html by speeding up Element::getAttribute()
        https://bugs.webkit.org/show_bug.cgi?id=90174

        Change argument types of Element::getAttribute*() from String to AtomicString
        https://bugs.webkit.org/show_bug.cgi?id=90246

Conflicts:

	Source/WebCore/ChangeLog
	Source/WebCore/dom/Document.cpp
	Source/WebCore/dom/Document.h

Conflicts:

	Source/WebCore/ChangeLog

Change-Id: I9ca3d2e883155e2ad08c3cb0c5912b935ebe9406