Test indenting an image element twice.

Initial state:
| <img>
|   src="../resources/abe.png"

After indenting once:
| <blockquote>
|   style="margin: 0 0 0 40px; border: none; padding: 0px;"
|   <#selection-anchor>
|   <img>
|     src="../resources/abe.png"
|   <#selection-focus>

After indenting again:
| <blockquote>
|   style="margin: 0 0 0 40px; border: none; padding: 0px;"
|   <blockquote>
|     style="margin: 0 0 0 40px; border: none; padding: 0px;"
|     <#selection-anchor>
|     <img>
|       src="../resources/abe.png"
|     <#selection-focus>