[css-grid] Add initial draft of CSS Grid Layout Test Plan
Merge pull request #623 from Igalia/css-grid-test-plan

[css-grid] Add initial draft of CSS Grid Layout Test Plan
Remove tests for inline style of calc() expressions

Serialization for calc() isn't specified, and WebKit and Blink disagree
on the value here. We're not testing that calc() works, so it is
sufficient to test the computed style.
Merge pull request #634 from bemjb/sit

Remove tests for inline style of calc() expressions