Verifies that asking for the scrollingElement of a document with null body or null documentElement doesn't crash

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".

PASS document.scrollingElement is document.documentElement
PASS nullbody.contentDocument.compatMode is "BackCompat"
PASS nullbody.contentDocument.body is null
PASS nullbody.contentDocument.scrollingElement is null
PASS nullroot.contentDocument.compatMode is "BackCompat"
PASS nullroot.contentDocument.documentElement is null
PASS nullroot.contentDocument.body is null
PASS nullroot.contentDocument.scrollingElement is null
PASS successfullyParsed is true

TEST COMPLETE