Remove the Element.prefix setter

LayoutTests/fast/dom/Element/prefix-setter-exception-expected.txt

Index: LayoutTests/fast/dom/Element/prefix-setter-exception-expected.txt
diff --git a/LayoutTests/fast/dom/Element/prefix-setter-exception-expected.txt b/LayoutTests/fast/dom/Element/prefix-setter-exception-expected.txt
deleted file mode 100644
index e170f17e8a2ed72b551c07f0f295be897a6b23c5..0000000000000000000000000000000000000000
--- a/LayoutTests/fast/dom/Element/prefix-setter-exception-expected.txt
+++ /dev/null
@@ -1,29 +0,0 @@
-CONSOLE WARNING: Setting 'Element.prefix' is deprecated, as it is read-only per DOM (http://dom.spec.whatwg.org/#element).
-Test for the implementation of DOM Level 3 Core API on Node Interface: prefix setter. INVALID_CHARACTER_ERR: Raised if the specified prefix contains an illegal character according to the XML version in use specified in the Document.xmlVersion attribute. http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-NodeNSPrefix
-
-On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
-
-
-PASS prefixedElem.prefix = "." threw exception InvalidCharacterError: Failed to set the 'prefix' property on 'Element': The prefix '.' is not a valid name..
-PASS prefixedElem.prefix is "before"
-PASS prefixedElem.prefix = "x." is "x."
-PASS prefixedElem.prefix is "x."
-PASS prefixedElem.prefix = "0a" threw exception InvalidCharacterError: Failed to set the 'prefix' property on 'Element': The prefix '0a' is not a valid name..
-PASS prefixedElem.prefix is "before"
-PASS prefixedElem.prefix = "a0" is "a0"
-PASS prefixedElem.prefix is "a0"
-PASS prefixedElem.prefix = "_0" is "_0"
-PASS prefixedElem.prefix is "_0"
-PASS prefixedElem.prefix = "×" threw exception InvalidCharacterError: Failed to set the 'prefix' property on 'Element': The prefix '×' is not a valid name..
-PASS prefixedElem.prefix is "before"
-PASS prefixedElem.prefix = "·" threw exception InvalidCharacterError: Failed to set the 'prefix' property on 'Element': The prefix '·' is not a valid name..
-PASS prefixedElem.prefix is "before"
-PASS prefixedElem.prefix = "aa" is "aa"
-PASS prefixedElem.prefix is "aa"
-PASS prefixedElem.prefix = "\n" threw exception InvalidCharacterError: Failed to set the 'prefix' property on 'Element': The prefix '
-' is not a valid name..
-PASS prefixedElem.prefix is "before"
-PASS successfullyParsed is true
-
-TEST COMPLETE
-