Compiler throws exception when `{{yield}}` is preceded by an element

[Conduitry]

If a {{yield}} tag is preceded by a DOM element, the compiler throws an exception here. child._state is undefined.

Attempting to compile this, for example, will trigger the exception:

<div></div>
{{yield}}

It doesn't happen with e.g. <div>{{yield}}</div>.

This wasn't happening before 1.18.0, so it's likely caused by the change to use fewer anchors.

[Rich-Harris]

fixed in 1.18.1