Node::lazyAttach shouldn't lie about being attached

LayoutTests/fast/dom/shadow/shadow-root-attached.html

Index: LayoutTests/fast/dom/shadow/shadow-root-attached.html
diff --git a/LayoutTests/fast/dom/shadow/shadow-root-attached.html b/LayoutTests/fast/dom/shadow/shadow-root-attached.html
index f5125fbd4085f5b059aadb57f46259eb2c86940c..e3a5a956143d5e64e785dd835e7eb1e44a8dfa46 100644
--- a/LayoutTests/fast/dom/shadow/shadow-root-attached.html
+++ b/LayoutTests/fast/dom/shadow/shadow-root-attached.html
@@ -21,6 +21,7 @@ var container = document.getElementById("container");
 
     shouldBe('internals.attached(light)', 'false');
     document.getElementById('container').appendChild(root);
+    document.body.offsetLeft; // cause a style recalc to trigger attachment.
     shouldBe('internals.attached(light)', 'true');
 })();
 
@@ -34,6 +35,7 @@ var container = document.getElementById("container");
 
     shouldBe('internals.attached(light)', 'false');
     document.getElementById('container').appendChild(root);
+    document.body.offsetLeft; // cause a style recalc to trigger attachment.
     shouldBe('internals.attached(light)', 'true');
 })();