Debugger: clear ICs on activating step-in to correctly flood accessor pairs.

test/mjsunit/debug-stepin-accessor-ic.js

+// Copyright 2014 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
+
+function get() {
+  return 3;                       // Break
+}                                 // Break
+
+function set(x) {
+  this.x = x;                     // Break
+}                                 // Break
+
+var o = {};
+Object.defineProperty(o, "get", { get : get });
+Object.defineProperty(o, "set", { set : set });
+
+function f() {
+  for (var i = 0; i < 10; i++) {  // Break
+    o.get;                        // Break
+    o.set = 1;                    // Break
+  }
+}                                 // Break
+
+var break_count = 0;
+var exception = null;
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    var source_line = exec_state.frame(0).sourceLineText();
+    assertTrue(source_line.indexOf("// Break") > 0);
+    exec_state.prepareStep(Debug.StepAction.StepIn, 1);
+    break_count++;
+  } catch (e) {
+    exception = e;
+  }
+}
+
+var Debug = debug.Debug;
+Debug.setListener(listener);
+
+debugger;                         // Break
+f();                              // Break
+
+Debug.setListener(null);          // Break
+assertEquals(86, break_count);
+assertNull(exception);