Convert CSS and Parser tests to runs/s tests

Convert CSS and Parser tests to runs/s tests
https://bugs.webkit.org/show_bug.cgi?id=86399

Reviewed by Ojan Vafai.

Use runPerSecond instead of run to measure results in function calls per second (run/s) instead of time (ms).
This allows us to continue measuring performance reliably even when WebKit's performance improves and results
become too small for Date.now()'s precision (around 15 ms).

It should also reduce perf. bots cycle time for slower tests because we limit the number of function calls by time.

* CSS/CSSPropertySetterGetter.html:
* CSS/CSSPropertyUpdateValue.html:
* Parser/css-parser-yui.html:
* Parser/simple-url.html:
* Parser/tiny-innerHTML.html:
* Parser/url-parser.html:
* Parser/xml-parser.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@117001 268f45cc-cd09-0410-ab3c-d52691b4dbfc