AS PRANKS go, it oozed vitriol. On March 17th, while employees at Bear Stearns were coming to terms with the implosion of their once-venerable investment bank, one of them stuck a $2 note to the revolving doors of the firm's midtown-Manhattan headquarters. That was the amount, per share, that Bear had fetched in a fire sale to JPMorgan Chase a day earlier, when the Federal Reserve was rushing to s