Make CharacterData.appendData() argument mandatory

LayoutTests/fast/dom/characterdata-appendData-argument-expected.txt

Index: LayoutTests/fast/dom/characterdata-appendData-argument-expected.txt
diff --git a/LayoutTests/fast/dom/characterdata-appendData-argument-expected.txt b/LayoutTests/fast/dom/characterdata-appendData-argument-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..6c9d52d681dd66b9752277d0c6e5d05a05b9eddc
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+++ b/LayoutTests/fast/dom/characterdata-appendData-argument-expected.txt
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+Tests that CharacterData.appendData() argument is mandatory.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS text.data is "abcd"
+PASS text.__proto__.__proto__ is CharacterData.prototype
+PASS text.appendData('efg') did not throw exception.
+PASS text.data is "abcdefg"
+PASS text.appendData() threw exception TypeError: Not enough arguments.
+PASS text.data is "abcdefg"
+PASS successfullyParsed is true
+
+TEST COMPLETE
+