Add performance tests for the Element.id getter and setter

Add performance tests for the Element.id getter and setter
https://bugs.webkit.org/show_bug.cgi?id=79209

Reviewed by Adam Barth.

This patch adds performance tests for the Element.id getter and setter.

The results of 10 runs in my local Chromium/Linux are as follows:

dom_attributes_id_getter.html:
median= 92.0 ms, stdev= 1.65151445649 ms, min= 89.0 ms, max= 96.0 ms
median= 87.5 ms, stdev= 1.84390889146 ms, min= 85.0 ms, max= 92.0 ms
median= 94.0 ms, stdev= 1.46543508898 ms, min= 90.0 ms, max= 95.0 ms
median= 86.0 ms, stdev= 1.66958078571 ms, min= 84.0 ms, max= 91.0 ms
median= 94.0 ms, stdev= 2.25610283454 ms, min= 103.0 ms, max= 98.0 ms
median= 86.0 ms, stdev= 1.49666295471 ms, min= 84.0 ms, max= 91.0 ms
median= 86.0 ms, stdev= 1.5321553446 ms, min= 84.0 ms, max= 90.0 ms
median= 86.0 ms, stdev= 2.20227155455 ms, min= 84.0 ms, max= 94.0 ms
median= 96.0 ms, stdev= 1.74570902501 ms, min= 101.0 ms, max= 99.0 ms
median= 86.0 ms, stdev= 1.63935963108 ms, min= 84.0 ms, max= 90.0 ms
median= 94.0 ms, stdev= 1.49248115566 ms, min= 90.0 ms, max= 95.0 ms
median= 88.0 ms, stdev= 5.20192272146 ms, min= 84.0 ms, max= 98.0 ms
median= 86.0 ms, stdev= 1.41067359797 ms, min= 84.0 ms, max= 89.0 ms
median= 86.0 ms, stdev= 1.48660687473 ms, min= 84.0 ms, max= 89.0 ms
median= 94.0 ms, stdev= 1.58113883008 ms, min= 93.0 ms, max= 97.0 ms
median= 86.0 ms, stdev= 1.95959179423 ms, min= 84.0 ms, max= 93.0 ms
median= 86.0 ms, stdev= 1.8547236991 ms, min= 84.0 ms, max= 92.0 ms
median= 86.0 ms, stdev= 1.39283882772 ms, min= 84.0 ms, max= 89.0 ms
median= 88.0 ms, stdev= 1.48660687473 ms, min= 85.0 ms, max= 90.0 ms
median= 86.5 ms, stdev= 2.3 ms, min= 84.0 ms, max= 93.0 ms

dom_attributes_id_setter.html:
median= 123.0 ms, stdev= 2.06397674406 ms, min= 119.0 ms, max= 128.0 ms
median= 119.0 ms, stdev= 1.92028643697 ms, min= 117.0 ms, max= 123.0 ms
median= 121.0 ms, stdev= 1.8781639971 ms, min= 118.0 ms, max= 123.0 ms
median= 123.0 ms, stdev= 2.21585198062 ms, min= 119.0 ms, max= 130.0 ms
median= 124.5 ms, stdev= 2.36378933071 ms, min= 119.0 ms, max= 129.0 ms
median= 122.0 ms, stdev= 2.4474476501 ms, min= 118.0 ms, max= 128.0 ms
median= 123.0 ms, stdev= 1.76351920885 ms, min= 118.0 ms, max= 125.0 ms
median= 119.0 ms, stdev= 1.79652442232 ms, min= 117.0 ms, max= 125.0 ms
median= 121.0 ms, stdev= 1.49916643506 ms, min= 119.0 ms, max= 123.0 ms
median= 119.5 ms, stdev= 1.85135085816 ms, min= 117.0 ms, max= 125.0 ms
median= 124.0 ms, stdev= 1.43090880213 ms, min= 120.0 ms, max= 124.0 ms
median= 122.0 ms, stdev= 1.45859521458 ms, min= 118.0 ms, max= 123.0 ms
median= 123.0 ms, stdev= 1.50332963784 ms, min= 120.0 ms, max= 124.0 ms
median= 123.0 ms, stdev= 1.3638181697 ms, min= 120.0 ms, max= 125.0 ms
median= 119.0 ms, stdev= 1.43527000944 ms, min= 117.0 ms, max= 121.0 ms
median= 122.5 ms, stdev= 1.71682847134 ms, min= 118.0 ms, max= 124.0 ms
median= 121.0 ms, stdev= 1.44481832768 ms, min= 118.0 ms, max= 123.0 ms
median= 120.0 ms, stdev= 1.40978721799 ms, min= 117.0 ms, max= 122.0 ms
median= 122.0 ms, stdev= 1.68522995464 ms, min= 119.0 ms, max= 125.0 ms
median= 122.0 ms, stdev= 1.55804364509 ms, min= 118.0 ms, max= 123.0 ms

* Bindings/dom_attributes_id_getter.html: Added.
* Bindings/dom_attributes_id_setter.html: Added.
* Bindings/resources/dom_attributes_common.js: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@108477 268f45cc-cd09-0410-ab3c-d52691b4dbfc