New i18n tests & results: CSS Logical

The CSS Logical Properties and Values 
<https://www.w3.org/TR/css-logical-1/> spec allows authors to specify 
margins, captions, etc. using declarations that are valid without change 
whether text is horizontal LTR or RTL, or vertical LR/RL. Values have 
names such as -start/-end, rather than -left/-right.

These new tests look at support for values in RTL and vertical LR/RL 
contexts. They cover block size, margins, padding, border 
width/style/color/radius, caption side, & floats.

The test results, and links to the tests themselves, can be found at
https://w3c.github.io/i18n-tests/results/css-logical.html