Clean up Jest initialization

test/setup-test-framework.js

@@ -1,3 +1,4 @@
+// `babel-jest` should be doing this instead, but apparently it's not working.
 require( 'core-js/modules/es7.object.values' );
 
 // Chai plugins

test/setup-wp-aliases.js

@@ -1,18 +1,14 @@
-const lazySetupAlias = object =>
-	name =>
-		Object.defineProperty( object, name, {
-			get: () => require( name ),
-		} );
-const lazySetupWpAlias = lazySetupAlias( global.wp );
-
-const entryPointNames = [
+// Set up `wp.*` aliases.  Handled by Webpack outside of the test build.
+[
 	'element',
 	'i18n',
 	'components',
 	'utils',
 	'blocks',
 	'date',
 	'editor',
-];
-
-entryPointNames.forEach( lazySetupWpAlias );
+].forEach( entryPointName => {
+	Object.defineProperty( global.wp, entryPointName, {
+		get: () => require( entryPointName ),
+	} );
+} );