URL tests from https://github.com/annevk/url/
new test for setRequestHeader() with value arguments empty string, null, undefined
Remove some tests that do not add anything over Aryeh's reflection tests.
Merge pull request #389 from Ms2ger/obsolete-tests

Remove some tests that do not add anything over Aryeh's reflection tests.
Merge pull request #385 from w3c/add_setrequestheader_empty_test

new test for setRequestHeader() with value arguments empty string, null,...
Fix issues: https://critic.hoppipolla.co.uk/r/300
Merge pull request #319 from annevk/url

URL tests from https://github.com/annevk/url/
Update window-properties.html to current WebIDL.

In particular, WebIDL now defines that members of the global object end up on the object itself;
see http://dev.w3.org/2006/webapi/WebIDL/#es-attributes (second bullet, second and third
sub-bullets).
Merge pull request #394 from Ms2ger/window-own-properties

Update window-properties.html to current WebIDL; r=zcorpan