The DOM L3 Core test:

  documentnormalizedocument10

tries to insert a second Element node into a Document. This might go wrong
straight away with a HIERARCHY_REQUEST_ERR, but if not it will certainly go
wrong when normalizeDocument is called as the document cannot possibly be
well-formed.

In any case the test is based on a flawed premise, that setting
'element-content-whitespace' to false and normalising will remove some spaces
from the middle of a Text node whose parent is not declared as containing
'element content'. This misunderstands what 'element content whitespace'
actually is.