getComputedStyle margin percentage test for CSS calc

getComputedStyle margin percentage test for CSS calc
https://bugs.webkit.org/show_bug.cgi?id=76130

Reviewed by Darin Adler.

Tests for future implementation of CSS3 calc() (see http://webkit.org/b/16662)

These tests are expected to 'fail', and will pass once calc() functionality is landed.
For now, they serve to demonstrate that the current code doesn't crash on these tests.

* css3/calc/getComputedStyle-margin-percentage-expected.txt: Added.
* css3/calc/getComputedStyle-margin-percentage.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105647 268f45cc-cd09-0410-ab3c-d52691b4dbfc