This tests pasting a blockquote into a blockquote. Nothing below should be double-blockquoted.
| "
        "
| <blockquote>
|   type="cite"
|   "one"
|   <br>
|   "two"
|   <br>
|   "three"
|   <br>
|     id="endContent"
|   "two<#selection-caret>"
|   <br>
| <blockquote>
|   type="cite"
|   <br>
| "
    "