Tests that media query stack is computed correctly when several stylesheets share the same URL.

Main style:
[expanded] 
element.style  { ()

[expanded] 
media="screen" (media-using-same-url.html)
@media not print (media-using-same-url.html:13 -> media-using-same-url.html:13:1)
#main  { (media-using-same-url.html:14 -> media-using-same-url.html:14:1)
color: white;

[expanded] 
media="screen" (media-using-same-url.html)
@media not print (media-using-same-url.html:5 -> media-using-same-url.html:5:1)
#main  { (media-using-same-url.html:6 -> media-using-same-url.html:6:1)
background: blue;

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