Execute <script> after a DOM insertion is completed.

This CL fixes two assertion failures. We should not execute <script> in
Node::insertedInto notification because it can prevent insertedInto
notifications for other nodes.

ASSERTION FAILED: !m_insertionPoint->inDocument()
../../third_party/WebKit/Source/core/dom/ContainerNodeAlgorithms.h(243) : void WebCore::ChildNodeRemovalNotifier::notifyNodeRemovedFromTree(WebCore::ContainerNode *)
1   0xe7cc3dd WebCore::ChildNodeRemovalNotifier::notifyNodeRemovedFromTree(WebCore::ContainerNode*)
2   0xe7c9fa1 WebCore::ChildNodeRemovalNotifier::notify(WebCore::Node*)
3   0xe7c5cc9 WebCore::ContainerNode::removeChild(WebCore::Node*, WebCore::ExceptionState&)
4   0xe90d3de WebCore::Node::remove(WebCore::ExceptionState&)

ASSERTION FAILED: m_formElementsWithState.contains(control)
../../third_party/WebKit/Source/core/html/FormController.cpp(523) : void WebCore::FormController::unregisterFormElementWithState(WebCore::HTMLFormControlElementWithState *)
1   0xd05f7ff WebCore::FormController::unregisterFormElementWithState(WebCore::HTMLFormControlElementWithState*)
2   0xd0b9633 WebCore::HTMLFormControlElementWithState::removedFrom(WebCore::ContainerNode*)
3   0xd0e63d9 WebCore::HTMLInputElement::removedFrom(WebCore::ContainerNode*)
4   0xe8b328f WebCore::ChildNodeRemovalNotifier::notifyNodeRemovedFromDocument(WebCore::Node*)
5   0xe8b5920 WebCore::ChildNodeRemovalNotifier::notifyDescendantRemovedFromDocument(WebCore::ContainerNode*)
6   0xe8b32c1 WebCore::ChildNodeRemovalNotifier::notifyNodeRemovedFromDocument(WebCore::Node*)
7   0xe8b0f57 WebCore::ChildNodeRemovalNotifier::notify(WebCore::Node*)
8   0xe8accc9 WebCore::ContainerNode::removeChild(WebCore::Node*, WebCore::ExceptionState&)
9   0xe9f43de WebCore::Node::remove(WebCore::ExceptionState&)


BUG=284726,284968

Review URL: https://chromiumcodereview.appspot.com/23557007

git-svn-id: svn://svn.chromium.org/blink/trunk@157495 bbb929c8-8fbe-4397-9dbb-9b2b20218538