Show contents of text nodes in jsDump.node

[Krinkle]

While writing unit tests for dom traversal I noticed that text nodes get dumped as <#text></<#text> (based on the nodeName for TextNode's ^[spec]).

The nodeValue (text content) is not dumped. This can make it rather difficult to figure out what went wrong as the jsDump outputs are the same for "Actual" and "Result" (whereas equal, comparing them by reference, returns false)