Debugger: fix stepping when break points are deactivated.

test/mjsunit/regress/regress-crbug-119800.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
 
-var break_count = 0;
+function f() {
+  1;
+  2;
+  3;
+}
+
+var Debug = debug.Debug;
 var exception = null;
+var breaks = [];
 
 function listener(event, exec_state, event_data, data) {
   if (event != Debug.DebugEvent.Break) return;
   try {
-    var source_line = exec_state.frame(0).sourceLineText();
-    print(source_line);
+    Debug.debuggerFlags().breakPointsActive.setValue(false);
+    breaks.push(exec_state.frame().sourceLineText().trimLeft());
     exec_state.prepareStep(Debug.StepAction.StepIn, 1);
-    break_count++;
   } catch (e) {
     exception = e;
   }
 }
 
-var Debug = debug.Debug;
 Debug.setListener(listener);
+Debug.setBreakPoint(f, 0, 0);
 
+f();
 
-function f() {
-  this.x = 1;
-}
+Debug.setListener(null);
+Debug.debuggerFlags().breakPointsActive.setValue(true);
 
-function g() {
-  new f();
-}
-
-Debug.setBreakPoint(g, 6, Debug.BreakPositionAlignment.BreakPosition);
-print(Debug.showBreakPoints(g, undefined,
-      Debug.BreakPositionAlignment.BreakPosition));
-
-g();
-Debug.setListener(null);
-
-assertEquals(6, break_count);
 assertNull(exception);
+assertEquals(breaks, ["1;", "2;", "3;", "}", "Debug.setListener(null);"]);