add test for custom global names for external modules

test/form/external-imports-custom-names/_config.js

@@ -0,0 +1,10 @@
+module.exports = {
+	description: 'allows global names to be specified for IIFE/UMD exports',
+	options: {
+		external: [ 'jquery' ],
+		globals: {
+			jquery: 'jQuery'
+		}
+	},
+	solo: true
+};

test/form/external-imports-custom-names/main.js

@@ -0,0 +1,5 @@
+import $ from 'jquery';
+
+$( function () {
+	$( 'body' ).html( '<h1>hello world!</h1>' );
+});