Remove Node.prefix so it's no longer visible to script.

LayoutTests/fast/dom/Node/initial-values-expected.txt

Index: LayoutTests/fast/dom/Node/initial-values-expected.txt
diff --git a/LayoutTests/fast/dom/Node/initial-values-expected.txt b/LayoutTests/fast/dom/Node/initial-values-expected.txt
index 059fc6db750ef5834abf34fae653ac475ce7a19f..f1b46cde6a5845e59e6b8216e7bd5f9eef096dbc 100644
--- a/LayoutTests/fast/dom/Node/initial-values-expected.txt
+++ b/LayoutTests/fast/dom/Node/initial-values-expected.txt
@@ -38,31 +38,26 @@ PASS attr.value is ''
 PASS comment.nodeName is '#comment'
 PASS comment.localName is null
 PASS comment.namespaceURI is null
-PASS comment.prefix is null
 PASS comment.nodeValue is 'foo'
 PASS comment.data is 'foo'
 PASS document.createCDATASection('foo') threw exception NotSupportedError: Failed to execute 'createCDATASection' on 'Document': This operation is not supported for HTML documents..
 PASS cdata.nodeName is '#cdata-section'
 PASS cdata.localName is null
 PASS cdata.namespaceURI is null
-PASS cdata.prefix is null
 PASS cdata.nodeValue is 'foo'
 PASS cdata.data is 'foo'
 PASS fragment.nodeName is '#document-fragment'
 PASS fragment.localName is null
 PASS fragment.namespaceURI is null
-PASS fragment.prefix is null
 PASS fragment.nodeValue is null
 PASS doc.nodeName is '#document'
 PASS doc.localName is null
 FAIL doc.namespaceURI should be http://www.w3.org/1999/xhtml (of type string). Was null (of type object).
-PASS doc.prefix is null
 PASS doc.nodeValue is null
 PASS doctype.nodeName is 'svg'
 PASS doctype.name is 'svg'
 PASS doctype.localName is null
 PASS doctype.namespaceURI is null
-PASS doctype.prefix is null
 PASS doctype.nodeValue is null
 Element creation using createElement on an HTML doc:
 PASS element.nodeName is 'PRE'
@@ -117,7 +112,6 @@ Processing instruction creation using createProcessingInstruction on an HTML doc
 PASS processingInstruction.nodeName is 'xml-stylesheet'
 PASS processingInstruction.localName is null
 PASS processingInstruction.namespaceURI is null
-PASS processingInstruction.prefix is null
 PASS processingInstruction.nodeValue is 'type="text/xsl" href="missing.xsl"'
 PASS processingInstruction.target is 'xml-stylesheet'
 PASS processingInstruction.data is 'type="text/xsl" href="missing.xsl"'
@@ -125,7 +119,6 @@ Processing instruction creation using createProcessingInstruction on an XHTML do
 PASS processingInstruction.nodeName is 'xml-stylesheet'
 PASS processingInstruction.localName is null
 PASS processingInstruction.namespaceURI is null
-PASS processingInstruction.prefix is null
 PASS processingInstruction.nodeValue is 'type="text/xsl" href="missing.xsl"'
 PASS processingInstruction.target is 'xml-stylesheet'
 PASS processingInstruction.data is 'type="text/xsl" href="missing.xsl"'
@@ -133,7 +126,6 @@ Text node creation using createTextNode on an HTML doc:
 PASS text.nodeName is '#text'
 PASS text.localName is null
 PASS text.namespaceURI is null
-PASS text.prefix is null
 PASS text.nodeValue is 'foo'
 PASS text.data is 'foo'
 PASS successfullyParsed is true