DevTools: shard inspector/elements tests for faster execution.

LayoutTests/inspector/elements/styles-2/parse-declaration-unterminated-comment-expected.txt

 Tests that CSSParser correctly parses declarations with unterminated comments.
 
 [expanded] 
 element.style  { ()
     color: red /* foo: bar;
 
 [expanded] 
 div  { (user agent stylesheet)
     display: block;
 
 [expanded] 
 element.style  { ()
     color: green;
 
 [expanded] 
 div  { (user agent stylesheet)
     display: block;