Check is_simple_api_call before IsCrossContextLazyAccessorPair, accessor could be null

Bug: chromium:779367
Change-Id: I0d361ffc9be1e271e91ce81c3e5cf70697c0ac0b
Reviewed-on: https://chromium-review.googlesource.com/749812Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49081}

src/compiler/access-info.cc

@@ -445,11 +445,11 @@ bool AccessInfoFactory::ComputePropertyAccessInfo(
               isolate());
           if (!accessor->IsJSFunction()) {
             CallOptimization optimization(accessor);
+            if (!optimization.is_simple_api_call()) return false;
             if (optimization.IsCrossContextLazyAccessorPair(*native_context_,
                                                             *map)) {
               return false;
             }
-            if (!optimization.is_simple_api_call()) return false;
 
             CallOptimization::HolderLookup lookup;
             holder =

test/mjsunit/regress/regress-crbug-779367.js

+// Copyright 2017 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
+
+function g(o) {
+  return o.x;
+}
+
+Object.defineProperty(g, 'x', {set(v) {}});
+
+g.prototype = 1;
+g(g);
+g(g);
+%OptimizeFunctionOnNextCall(g);
+g(g);