yui: Fix skin tests for latest Chrome/Android 4.4

New Chrome and Android return the full value declaration with `getComputedStyle` for font properties such as `textDecoration`. They return:

`underline solid rgb(0, 0, 0)`

Instead of just:

`underline`

Since we don't normalize `getComputedStyle` for shorthand like that, the tests just need to be fixed.

\cc @msweeney