Re: [html-tests] step{Up,Down}() reserializes the value, & valid time string allows multiple formats (#4600)

Notifying @Ms2ger, @ayg, @gsnedders, @jdm, @jgraham, @sideshowbarker, @zcorpan, and @zqzhang. *([Learn how reviewing works](https://github.com/w3c/web-platform-tests/blob/master/README.md#test-review).)*

View on GitHub: https://github.com/w3c/web-platform-tests/pull/4600#issuecomment-274366372

Received on Sunday, 22 January 2017 22:44:51 UTC