test(transpiler): add a cycle import spec

tools/transpiler/spec/cycle.js

@@ -0,0 +1,5 @@
+import {foo} from './cycle_spec';
+
+export function cycle() {
+  return foo;
+}

tools/transpiler/spec/cycle_spec.js

@@ -0,0 +1,13 @@
+import {describe, it, expect} from 'test_lib/test_lib';
+import {cycle} from './cycle';
+
+export function main() {
+  describe('cycle', function() {
+    it('should work', function() {
+      expect(cycle()).toBe(true);
+    });
+  });
+}
+
+export var foo = true;
+