Tests how DOM domain works with getOuterHTML.

getOuterHTML(declarativeId, includeShadowDOM=false):
{
    id : <number>
    result : {
        outerHTML : <div id="declarative">            </div>
    }
    sessionId : <string>
}

getOuterHTML(declarativeId, includeShadowDOM=true):
{
    id : <number>
    result : {
        outerHTML : <div id="declarative"><template shadowrootmode="open">         <div>contents</div>       </template>            </div>
    }
    sessionId : <string>
}

getOuterHTML(jsId, includeShadowDOM=false):
{
    id : <number>
    result : {
        outerHTML : <div id="js">     </div>
    }
    sessionId : <string>
}

getOuterHTML(jsId, includeShadowDOM=true):
{
    id : <number>
    result : {
        outerHTML : <div id="js"><template shadowrootmode="open"><div>more contents</div></template>     </div>
    }
    sessionId : <string>
}