Revert of [Atomics] Remove Atomics code stubs; use TF ops

src/compiler/opcodes.h

 // Copyright 2013 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.
 
 #ifndef V8_COMPILER_OPCODES_H_
 #define V8_COMPILER_OPCODES_H_
 
 #include <iosfwd>
 
 // Opcodes for control operators.
@@ skipping 332 matching lines @@
   V(LoadStackPointer)           \
   V(LoadFramePointer)           \
   V(LoadParentFramePointer)     \
   V(CheckedLoad)                \
   V(CheckedStore)               \
   V(Int32PairAdd)               \
   V(Int32PairSub)               \
   V(Int32PairMul)               \
   V(Word32PairShl)              \
   V(Word32PairShr)              \
-  V(Word32PairSar)              \
-  V(AtomicLoad)
+  V(Word32PairSar)
 
 #define VALUE_OP_LIST(V) \
   COMMON_OP_LIST(V)      \
   SIMPLIFIED_OP_LIST(V)  \
   MACHINE_OP_LIST(V)     \
   JS_OP_LIST(V)
 
 // The combination of all operators at all levels and the common operators.
 #define ALL_OP_LIST(V) \
   CONTROL_OP_LIST(V)   \
@@ skipping 65 matching lines @@
   }
 };
 
 std::ostream& operator<<(std::ostream&, IrOpcode::Value);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_OPCODES_H_