Fix spec compliance error for DOMDocument::getElementsByTagNameNS

Spec link: https://dom.spec.whatwg.org/#concept-getelementsbytagnamens
Spec says we should match any namespace when '*'

Fix spec compliance error for DOMDocument::getElementsByTagNameNS

Spec link: https://dom.spec.whatwg.org/#concept-getelementsbytagnamens
Spec says we should match any namespace when '*' is provided. This was
however not the case: elements that didn't have a namespace were not
returned. This patch fixes the error by modifying the namespace check.

Closes GH-11343.

show more ...