include test for number specifiers

packages/babel-plugin-transform-es2015-modules-systemjs/test/fixtures/systemjs/imports-numbered/actual.js

@@ -0,0 +1,2 @@
+import "2";
+import "1";

packages/babel-plugin-transform-es2015-modules-systemjs/test/fixtures/systemjs/imports-numbered/expected.js

@@ -0,0 +1,8 @@
+System.register(["2", "1"], function (_export, _context) {
+  "use strict";
+
+  return {
+    setters: [function (_2) {}, function (_1) {}],
+    execute: function () {}
+  };
+});