Remove Babel (#1074)

* Test helpers no longer rely on Babel.

* Behaviours are no longer imported.

* Removed Babel dependency.

* Fixed linter errors.

test/ownership/CanReclaimToken.test.js

@@ -1,5 +1,4 @@
-
-import expectThrow from '../helpers/expectThrow';
+const { expectThrow } = require('../helpers/expectThrow');
 
 const CanReclaimToken = artifacts.require('CanReclaimToken');
 const BasicTokenMock = artifacts.require('BasicTokenMock');