Move HTMLTable*Element.insert{Row,Cell}'s argument default into IDL file

Source/core/html/HTMLTableElement.cpp

Index: Source/core/html/HTMLTableElement.cpp
diff --git a/Source/core/html/HTMLTableElement.cpp b/Source/core/html/HTMLTableElement.cpp
index 83670de0e53639c2b40f1ee8f5e4cd6e17413075..f2dccb02fece1fe417f3caffbb7498521d334798 100644
--- a/Source/core/html/HTMLTableElement.cpp
+++ b/Source/core/html/HTMLTableElement.cpp
@@ -168,12 +168,6 @@ HTMLTableSectionElement* HTMLTableElement::lastBody() const
     return toHTMLTableSectionElement(Traversal<HTMLElement>::lastChild(*this, HasHTMLTagName(tbodyTag)));
 }
 
-PassRefPtrWillBeRawPtr<HTMLElement> HTMLTableElement::insertRow(ExceptionState& exceptionState)
-{
-    // The default 'index' argument value is -1.
-    return insertRow(-1, exceptionState);
-}
-
 PassRefPtrWillBeRawPtr<HTMLElement> HTMLTableElement::insertRow(int index, ExceptionState& exceptionState)
 {
     if (index < -1) {