Revert "[proxy] Fix invalid call to getter in [[Get/Set]]"

This reverts commit 14165a47.

Reason for revert: Fix is incomplete, will reland soon.

Original change's description:
> [proxy] Fix invalid call to getter in [[Get/Set]]
> 
> Fixes the implementation of step 9 in the Proxy's internal [[Get]]
> method:
> 
> Let targetDesc be ? target.[[GetOwnProperty]](P)
> 
> If P is an accessor, this should not result in a call to the getter.
> Likewise in [[Set]].
> 
> https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver
> 
> Bug: chromium:776338
> Change-Id: Ic06b7eeac6a1ef9606ddda6fa9d6d58b709702fb
> Reviewed-on: https://chromium-review.googlesource.com/731123
> Reviewed-by: Georg Neis <neis@chromium.org>
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#48813}

TBR=neis@chromium.org,jgruber@chromium.org

Change-Id: I92a11791b3c6a73ada1f72fe4193c25e7a054746
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:776338
Reviewed-on: https://chromium-review.googlesource.com/732877Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48815}

src/builtins/builtins-proxy-gen.cc

@@ -494,7 +494,7 @@ void ProxiesCodeStubAssembler::CheckGetSetTrapResult(
   Node* instance_type = LoadInstanceType(target);
   TryGetOwnProperty(context, target, target, map, instance_type, name,
                     &if_found_value, &var_value, &var_details, &var_raw_value,
-                    check_passed, &check_in_runtime, kReturnAccessorPair);
+                    check_passed, &check_in_runtime);
 
   BIND(&if_found_value);
   {

test/mjsunit/regress/regress-776338.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.
-
-const obj = {};
-Object.defineProperty(obj, 'value', {
-  enumerable: true,
-  configurable: true,
-  get: function() {
-    assertUnreachable();
-  }
-});
-
-const get = function(target, prop) {
-  if (prop === 'value') {
-    return 'yep';
-  }
-  return Reflect.get(target, prop)
-};
-
-const proxy = new Proxy(obj, { get });
-assertEquals('yep', proxy.value);