Remove --stop-at flag from several backends.

src/x64/builtins-x64.cc

 // Copyright 2012 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 649 matching lines @@
     // Continue loop if not done.
     __ bind(&loop_check);
     __ subp(rcx, Immediate(kPointerSize));
     __ j(greater_equal, &loop_header, Label::kNear);
   }
 
   // TODO(rmcilroy): List of things not currently dealt with here but done in
   // fullcodegen's prologue:
   //  - Support profiler (specifically profiling_counter).
   //  - Call ProfileEntryHookStub when isolate has a function_entry_hook.
-  //  - Allow simulator stop operations if FLAG_stop_at is set.
   //  - Code aging of the BytecodeArray object.
 
   // Load accumulator, register file, bytecode offset, dispatch table into
   // registers.
   __ LoadRoot(kInterpreterAccumulatorRegister, Heap::kUndefinedValueRootIndex);
   __ movp(kInterpreterRegisterFileRegister, rbp);
   __ addp(kInterpreterRegisterFileRegister,
           Immediate(InterpreterFrameConstants::kRegisterFilePointerFromFp));
   __ movp(kInterpreterBytecodeOffsetRegister,
           Immediate(BytecodeArray::kHeaderSize - kHeapObjectTag));
@@ skipping 2171 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64