Tests that disabling shorthand removes the "overriden" mark from the UA shorthand it overrides.

Before disable
[expanded] 
element.style { ()
    margin: 10px;

[expanded] 
body { (user agent stylesheet)
    display: block;
/-- overloaded --/     margin: 8px;

After disable
[expanded] 
element.style { ()
/-- overloaded --/ /-- disabled --/     /* margin: 10px; */

[expanded] 
body { (user agent stylesheet)
    display: block;
    margin: 8px;

After enable
[expanded] 
element.style { ()
    margin: 10px;

[expanded] 
body { (user agent stylesheet)
    display: block;
/-- overloaded --/     margin: 8px;