Embroider builds failing due to did-intersect-mock

[elwayman02]

            TypeError: Attempted to replace instances which is already replaced
                at eval (webpack://dummy/../../sinon/lib/sinon/sandbox.js?:166:15)
                at Array.forEach (<anonymous>)
                at verifyNotReplaced (webpack://dummy/../../sinon/lib/sinon/sandbox.js?:164:5)
                at Sandbox.replace (webpack://dummy/../../sinon/lib/sinon/sandbox.js?:187:5)
                at mockDidIntersect (webpack://dummy/../rewritten-packages/ember-scroll-modifiers.e10ccf07/test-support/did-intersect-mock.js?:122:9)
                at Object.eval (webpack://dummy/./tests/integration/modifiers/did-intersect-mock-test.js?:20:127)

[elwayman02]

Update: This is because the sinon.replace calls don't seem to be cleaned up between tests - maybe we need to try sinon.stub instead?