break declaration grouping on non-declaration nodes (fixes #2022)

src/compile/Component.ts

@@ -865,7 +865,7 @@ export default class Component {
 					}
 				} else {
 					if (node.type !== 'ExportNamedDeclaration') {
-						if (!parent) current_group = null;
+						if (!parent || parent.type === 'Program') current_group = null;
 					}
 				}
 			},

test/runtime/samples/reactive-values-exported/main.svelte

@@ -1,11 +1,10 @@
 <script>
-	export let x;
+	export let x, y
 
-	export let y;
 	$: y = x;
 
 	export let z;
 	$: z = x;
 </script>
 
-<p>{x} {y} {z}</p>
+<p>{x} {y} {z}</p>