[Interpreter] Add test for sloppy mode receiver replacement.

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index bec2afab2f5789c5e0a720ef29c8bd6034eaa098..c09530dce28b675f401e5761a37f5abcc2854835 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -712,9 +712,6 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   //  - Support profiler (specifically profiling_counter).
   //  - Call ProfileEntryHookStub when isolate has a function_entry_hook.
   //  - Allow simulator stop operations if FLAG_stop_at is set.
-  //  - Deal with sloppy mode functions which need to replace the
-  //    receiver with the global proxy when called as functions (without an
-  //    explicit receiver object).
   //  - Code aging of the BytecodeArray object.
 
   // Perform stack guard check.