test cases for concatenation order independence.

We should use a strategy similar to opticss (before and after cascade comparison) to verify that concatenation order changes don't break css-blocks's resolution.

Start by reviewing css-blocks's cascade-resolution behavior and opticss's before-and-after cascade comparison approach. Locate the existing resolution test entry points, then define cases covering changed concatenation order. Done means the tests verify that concatenation order changes do not alter css-blocks's resolution.

Written by the indexing model from the issue text.