[debugger] remove step count parameter from prepare step.

test/mjsunit/debug-step-4.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 35 matching lines @@
     f();
   }
 }
 function h() {
   state = [-1, -1, -1];
   for (state[0] = 0; state[0] < 3; state[0]++) {
     g();
   }
 }
 
-function TestCase(step_count, expected_final_state) {
-  print("Test case, step count: " + step_count);
-
+function TestCase(expected_final_state) {
   var listener_exception = null;
   var state_snapshot;
   var listener_state;
   var bp;
 
   function listener(event, exec_state, event_data, data) {
     print("Here ("+event+"/"+listener_state+"): " +
         exec_state.frame(0).sourceLineText());
     try {
       if (event == Debug.DebugEvent.Break) {
         if (listener_state == 0) {
           Debug.clearBreakPoint(bp);
-          exec_state.prepareStep(Debug.StepAction.StepNext, step_count);
+          exec_state.prepareStep(Debug.StepAction.StepNext);
           listener_state = 1;
         } else if (listener_state == 1) {
           state_snapshot = String(state);
           print("State: " + state_snapshot);
           Debug.setListener(null);
           listener_state = 2;
         }
       }
     } catch (e) {
       listener_exception = e;
@@ skipping 13 matching lines @@
     assertUnreachable();
   }
 
   assertEquals(expected_final_state, state_snapshot);
 }
 
 
 // Warm-up -- make sure all is compiled and ready for breakpoint.
 h();
 
-TestCase(0, "0,0,-1");
-TestCase(1, "0,0,-1");
-TestCase(2, "0,0,0");
-TestCase(5, "0,0,1");
-TestCase(8, "0,0,2");
+TestCase("0,0,-1");