xmldom: Creation-time XML Name/QName validation is bypassable via an embedded line terminator, allowing injection on the default serialization path

Summary An embedded line terminator bypasses xmldom's always-on, WHATWG-mandated creation-time name validation. createElementNS, createAttributeNS, createDocumentType, and createAttribute should reject a malformed qualified name with InvalidCharacterError, but a name whose first line is well-form...