Add a basic sky-element custom element

sky/tests/modules/resources/multiple-scripts-child.sky

Index: sky/tests/modules/resources/multiple-scripts-child.sky
diff --git a/sky/tests/modules/resources/multiple-scripts-child.sky b/sky/tests/modules/resources/multiple-scripts-child.sky
index dd3e5eaac81e9b15066a69b8c65ac41f3e77560e..c46aeb6327e4105a03ae13e18ab9b725b25e49ba 100644
--- a/sky/tests/modules/resources/multiple-scripts-child.sky
+++ b/sky/tests/modules/resources/multiple-scripts-child.sky
@@ -2,7 +2,7 @@
 <script>
 final String one = 'one';
 bool oneInit = false;
-void init() {
+void _init(_) {
     oneInit = true;
 }
 final conflict = 'one';
@@ -10,7 +10,7 @@ final conflict = 'one';
 <script>
 final String two = 'two';
 bool twoInit = false;
-void init() {
+void _init(_) {
     twoInit = true;
 }
 final conflict = 'two';