Bug 89971 [Viewers] Viewers that use IViewerLabelProvider do too many instanceof checks
M6 Checking our viewer the calls to buildLabel are doing too many instanceof checks. As a result certain viewers (such as the table viewer) are twice as slow as they were in 3.0 due to these checks. I have written some performance suites to test the Table, Tree, List and Combo viewers. Table and Tree have this issue.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TableViewer.java
Object e = item.getData();
			if (e != null)
				list.add(e);
		}
		return list;
	}
	/**
	 * Returns this table viewer's table control.
	 * 
	 * @return the table control
	 */
	public Table getTable() {
		return table;
	}
	/*
	 *  (non-Javadoc)
	 * @see org.eclipse.jface.viewers.ContentViewer#hookControl(org.eclipse.swt.widgets.Control)
	 */
	protected void hookControl(Control control) {
		super.hookControl(control);
		Table tableControl = (Table) control;
		tableControl.addMouseListener(new MouseAdapter() {
			public void mouseDown(MouseEvent e) {
				tableViewerImpl.handleMouseDown(e);
			}
		});
	}
	/*
	 * Returns the index where the item should be inserted.
	 */