Tests that proper source lines are reported for the parsed styles.

[expanded] 
element.style { ()

[expanded] 
#main, .at_line_49 { (styles-sour…per.html:50 -> styles-source-lines-helper.html:50:2)
    border: 1px solid red;

[expanded] 
#main, .at_line_41 { (styles-sour…per.html:43 -> styles-source-lines-helper.html:43:2)
    font-size: 10px;

[expanded] 
#main, .at_line_26 { (styles-sour…per.html:29 -> styles-source-lines-helper.html:29:2)
    font-family: /* Comment in value */ courier;

[expanded] 
#main, .at_line_11::before { (styles-sour…per.html:15 -> styles-source-lines-helper.html:15:2)
    color: red;
    content: "Before";

[expanded] 
div { (user agent stylesheet)
    display: block;
    unicode-bidi: isolate;