Added ref tests for the dir attribute.

http://www.w3.org/html/wg/drafts/html/CR/dom.html#the-dir-attribute

Reftest that exercises many parts of the dir attribute spec.

In particular, Chromium passes and Opera fails the test "If the element is an input element whose type attribute is in the Text, and the dir attribute is in the auto state, if the element's value contains a character of bidirectional character type AL and there is no character of bidirectional character type L anywhere before it in the element's value, then the directionality of the element is 'rtl'".

Both Chromium and Opera fail many tests, including "If the attribute is a directionality-capable attribute and the element's dir attribute is in the auto state, and the first character (in logical order) of the attribute's value that is of bidirectional character type L, AL, or R, is of bidirectional character type AL or R, the directionality of the attribute is 'rtl'."