Revert "[stubs] Properly convert the receiver for GetPropertyStub."

This reverts commit 26fdb617f5.

Reason for revert: v8:6378

Original change's description:
> [stubs] Properly convert the receiver for GetPropertyStub.
> 
> Call ToObject on the GetPropertyStub input first, so that lookups on
> Strings and other primitives don't automatically hit the runtime, i.e.
> as the stub is also used to lookup the special @@split and @@replace
> symbols for various String builtins.
> 
> BUG=v8:5269
> R=​ishell@chromium.org
> 
> Change-Id: I5dbbc84aa2051173bf10be71c782fbe448481034
> Reviewed-on: https://chromium-review.googlesource.com/488441
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#44961}

TBR=ishell@chromium.org,bmeurer@chromium.org
# Not skipping CQ checks because original CL landed > 1 day ago.
BUG=v8:5269

Change-Id: I1e2e83b492d82656ead81ea35adbbcf5d324d2b8
Reviewed-on: https://chromium-review.googlesource.com/500135
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45206}

src/code-stubs.cc

@@ -856,10 +856,6 @@ TF_STUB(GetPropertyStub, CodeStubAssembler) {
         Goto(if_bailout);
       };
 
-  // Ensure that the {object} is actually a JSReceiver.
-  Callable callable = CodeFactory::ToObject(isolate());
-  object = CallStub(callable, context, object);
-
   TryPrototypeChainLookup(object, key, lookup_property_in_holder,
                           lookup_element_in_holder, &return_undefined,
                           &call_runtime);