[turbofan] Add a regression test

Bug: v8:9087
Change-Id: Ibc21d7e5619e4e6a0edc98cb0bd12e67ab2f6643
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1554690Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60657}

test/mjsunit/compiler/regress-9087.js

+// Copyright 2019 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 constructor() {}
+const obj = Object.create(constructor.prototype);
+
+for (let i = 0; i < 1020; ++i) {
+  constructor.prototype["x" + i] = 42;
+}
+
+function foo() {
+  return obj instanceof constructor;
+}
+
+assertTrue(foo());
+assertTrue(foo());
+%OptimizeFunctionOnNextCall(foo);
+assertTrue(foo());