Remove all children of the node from the existing DOMDocument.
Unnecessary boolean comaprison skipped.
Merge pull request #9 from cs-shadow/8.x-1.x

Remove all children of the entity's embed code DOMNode when doing the embedding.
Merge branch '8.x-1.x' into core-2217877-applied

Conflicts:
	lib/Drupal/entity_embed/Plugin/Filter/EntityEmbedFilter.php