Make %DebugPushPromise more robust wrt fuzzing.

test/mjsunit/regress/regress-crbug-401915.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: --allow-natives-syntax --expose-debug-as debug
 
 Debug = debug.Debug;
 Debug.setListener(function() {});
+Debug.setBreakOnException();
 
-function f() {
-  for (var i = 0; i < 100; i++) {
-    %OptimizeFunctionOnNextCall(f, "osr");
+try {
+  try {
+    %DebugPushPromise(new Promise(function() {}));
+  } catch (e) {
   }
+  throw new Error();
+} catch (e) {
 }
 
-Debug.setBreakPoint(f, 0, 0);
-f();
-f();
 Debug.setListener(null);