Debugger: use debug break slot to break on call.

test/mjsunit/debug-stepframe-clearing.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-debug-as debug
 
 // This test ensures that IC learning doesn't interfere with stepping into
 // property accessor. f1()'s ICs are allowed to learn to a monomorphic state,
 // and the breakpoints flooding get() are allowed to expire, then we ensure
 // that we can step into get() again later (when k == 1).
 function f1() {
   for (var k = 0; k < 2; k++) {     // Break 1
     var v10 = 0;                    // Line 2
     for (var i = 0; i < 10; i++) {  // Line 3
       var v12 = o.slappy;           // Line 4
       var v13 = 3                   // Line 5
     }                               // Line 6
     print("break here");            // Break 3
   }                                 // Line 8
-  print("exiting f1");              // Line 9 (dummy break)
+  print("exiting f1");              // Break 4
 }
 
 function get() {
   var g0 = 0;                       // Break 2
   var g1 = 1;
   return 3;
 }
 
 
 var o = {};
@@ skipping 23 matching lines @@
       // go monomorphic.
       assertEquals(break_count, match_value);
     } else if (break_count === 3) {
       // 3: back to frame stepping. Does the monomorphic slappy accessor
       // call still have the ability to break like before?
       assertEquals(break_count, match_value);
       Debug.clearBreakPoint(bp_f1_line7);
       exec_state.prepareStep(Debug.StepAction.StepFrame, 1);
     } else {
       assertEquals(4, break_count);
-      assertEquals(2, match_value);
+      assertEquals(4, match_value);
       // Apparently we can still stop in the accessor even though we cleared
       // breakpoints earlier and there was a monomorphic step.
       // Allow running to completion now.
       Debug.clearBreakPoint(bp_f1_line9);
     }
 
     break_count++;
   } catch (e) {
     print(e + e.stack);
     exception = e;
@@ skipping 13 matching lines @@
   bp_f1_line7 = Debug.setBreakPoint(f1, 7);
   bp_f1_line9 = Debug.setBreakPoint(f1, 9);
 
   debugger;                         // Break 0
   f1();
   Debug.setListener(null);
   assertTrue(break_count === 5);
 }
 
 assertNull(exception);