chore: require expect, fix matrix (#1374)

this is otherwhise not always available and breaks our internal
integration tests

Author: patricebender

db-service/test/cqn4sql/nested-projections.test/expand-structures.spec.js

@@ -4,6 +4,7 @@ const cds = require('@sap/cds')
 const { loadModel } = require('../helpers/model')
 
 const { expectCqn } = require('../helpers/expectCqn')
+const { expect } = cds.test
 
 let cqn4sql = require('../../../lib/cqn4sql')