Fix the debugger to finish correctly.

A previous patch I submitted to try and keep the $finish time
events missed the case of an infinite loop that did not advance
the micro time step which then prevents the debugger from
generating a finish (you can interrupt an infinite loop, but you
could not finish out of it). This patch adds a check for a
finish after each debugger call to fix this problem.

vvp/schedule.cc

@@ -623,6 +623,8 @@ void schedule_simulate(void)
 	    if (schedule_stopped_flag) {
 		  schedule_stopped_flag = false;
 		  stop_handler(0);
+		  // You can finish from the debugger without a time change.
+		  if (!schedule_runnable) break;
 		  continue;
 	    }