Tests that adding a new blank property works.

Before append:
[expanded] 
element.style { ()
    font-size: 12px;

[expanded] 
div { (user agent stylesheet)
    display: block;

After insertion at index 0:
[expanded] 
element.style { ()
    margin-left: 3px;
    font-size: 12px;

[expanded] 
div { (user agent stylesheet)
    display: block;

After appending and changing a 'compound' property:
[expanded] 
element.style { ()
    margin-left: 3px;
    font-size: 12px;
    color: red;
    font-weight: bold;

[expanded] 
div { (user agent stylesheet)
    display: block;

After insertion at index 2:
[expanded] 
element.style { ()
    margin-left: 3px;
    font-size: 12px;
/-- overloaded --/     third-property: third-value;
    color: red;
    font-weight: bold;

[expanded] 
div { (user agent stylesheet)
    display: block;