Bug 203709 NullPointerException in TableAreaLayout
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/layout/pdf/cache/TableAreaLayout.java
/*
		 * 1. resolve drop conflict, formailize current row.
		 * 2. resolve row height
		 * 
		 */
		hasDropCell = !finished;
		Row lastRow = getPreviousRow();
		if(lastRow==null && existDropCells() &&(!LayoutUtil.isRepeatableRow( (IRowContent)rowArea.getContent( ))))
		{
			lastRow = unresolvedRow;
		}
		Row row = new Row(rowArea, startCol, endCol, finished );
		int height = specifiedHeight;
		
		
		for(int i=startCol; i<=endCol; i++)
		{
			CellArea lastCell = null;
			if(lastRow!=null)
			{
				lastCell = lastRow.getCell( i );
			}
			CellArea cell = row.getCell( i );
			if(lastCell!=null 
					&&(lastCell.getRowSpan( )>1 || isDropCell( lastCell )))
			{
				 
				if(cell!=null)
				{
					row.remove( i );