Make breakpoint commands work again. Added a PerformAction to the stop info -...

Make breakpoint commands work again.  Added a PerformAction to the stop info - actions are run when the
stop event is pulled from the event queue.  Then made the StopInfoBreakpoint's PerformAction do the 
breakpoint command.
Also fixed the StopInfoBreakpoint's GetDescription so it gets the breakpoint location info, not the breakpoint
site info.

llvm-svn: 110637