This is the modified version of W3C's CSS2.1 test suite.

http://www.w3.org/Style/CSS/Test/CSS2.1/20100127/html4/chapter-13.htm

We maintain the hand-modified version because adding unmodified printing
related tests into LayoutTests/css2.1 directory doesn't make sense at all.

We need the following modifications to add W3C's test into this directory:

- Eliminate tabs.
- Add dumpAsText() call.
- Add test() function and implement it using testRunner functions.
- Call test() function using runPrintintTest(test) from body's onload.
- Add id attributes for elements in question.

FIXME: page-margin-* aren't added yet. We may need
       testRunner APIs to test margins.