Bug 196257 NPE when call ArgumentInfoList.argumentsIterator()
When call ArgumentInfoList.argumentsIterator(), it will throw NPE sometimes. This is caused the inner "arguments" member may not initialized when call this method.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/scripts/MethodInfo.java
/**
	 * Returns the internal Java Method instance.
	 * 
	 * @return the internal Java Method instance
	 */
	protected Method getMethod( )
	{
		return method;
	}
	/**
	 * Returns the iterator of argument definition. Each one is a list that
	 * contains <code>ArgumentInfoList</code>.
	 * 
	 * @return iterator of argument definition.
	 */
	public Iterator argumentListIterator( )
	{
		return arguments.iterator( );
	}
	/**
	 * Returns the resource key for tool tip.
	 * 
	 * @return the resource key for tool tip
	 */
	public String getToolTipKey( )
	{
		return StringUtil.EMPTY_STRING;
	}
	/**
	 * Returns the display string for the tool tip of this method.