Tests that per document Node count is correctly calculated by the Memory agent. Bug 74100. Bug 74298.

result = [
    {
        "title": "div",
        "size": 1,
        "nodeCount": [
            {
                "nodeName": "div",
                "count": 1
            }
        ],
        "listenerCount": [
            {
                "type": "mouseover",
                "count": 1
            },
            {
                "type": "click",
                "count": 1
            }
        ]
    },
    {
        "title": "div",
        "size": 1,
        "nodeCount": [
            {
                "nodeName": "div",
                "count": 1
            }
        ],
        "listenerCount": [
            {
                "type": "mouseover",
                "count": 1
            },
            {
                "type": "click",
                "count": 1
            }
        ]
    },
    {
        "title": "#document",
        "documentURI": "...about:blank",
        "size": 3,
        "nodeCount": [
            {
                "nodeName": "body",
                "count": 1
            },
            {
                "nodeName": "head",
                "count": 1
            },
            {
                "nodeName": "html",
                "count": 1
            }
        ],
        "listenerCount": []
    },
    {
        "title": "#document",
        "documentURI": "...dom-statistics.html",
        "size": 23,
        "nodeCount": [
            {
                "nodeName": "#text",
                "count": 13
            },
            {
                "nodeName": "a",
                "count": 2
            },
            {
                "nodeName": "body",
                "count": 1
            },
            {
                "nodeName": "div",
                "count": 1
            },
            {
                "nodeName": "head",
                "count": 1
            },
            {
                "nodeName": "html",
                "count": 1
            },
            {
                "nodeName": "iframe",
                "count": 1
            },
            {
                "nodeName": "p",
                "count": 1
            },
            {
                "nodeName": "script",
                "count": 2
            }
        ],
        "listenerCount": [
            {
                "type": "click",
                "count": 2
            },
            {
                "type": "mouseover",
                "count": 1
            }
        ]
    }
]