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

src/compiler/arm64/code-generator-arm64.cc

Index: src/compiler/arm64/code-generator-arm64.cc
diff --git a/src/compiler/arm64/code-generator-arm64.cc b/src/compiler/arm64/code-generator-arm64.cc
index 6a96d7eb5b31264353c9eef1a3c668cbb8be33ce..57e1e4661269218eb32f12356b93268e98e1359a 100644
--- a/src/compiler/arm64/code-generator-arm64.cc
+++ b/src/compiler/arm64/code-generator-arm64.cc
@@ -472,13 +472,6 @@
     }                                                                       \
   } while (0)
 
-#define ASSEMBLE_ATOMIC_LOAD_INTEGER(asm_instr)                       \
-  do {                                                                \
-    __ asm_instr(i.OutputRegister(),                                  \
-                 MemOperand(i.InputRegister(0), i.InputRegister(1))); \
-    __ Dmb(InnerShareable, BarrierAll);                               \
-  } while (0)
-
 void CodeGenerator::AssembleDeconstructFrame() {
   const CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
   if (descriptor->IsCFunctionCall() || descriptor->UseNativeStack()) {
@@ -1410,23 +1403,6 @@
       break;
     case kCheckedStoreFloat64:
       ASSEMBLE_CHECKED_STORE_FLOAT(64);
-      break;
-    case kAtomicLoadInt8:
-      ASSEMBLE_ATOMIC_LOAD_INTEGER(Ldrsb);
-      break;
-    case kAtomicLoadUint8:
-      ASSEMBLE_ATOMIC_LOAD_INTEGER(Ldrb);
-      break;
-    case kAtomicLoadInt16:
-      ASSEMBLE_ATOMIC_LOAD_INTEGER(Ldrsh);
-      break;
-    case kAtomicLoadUint16:
-      ASSEMBLE_ATOMIC_LOAD_INTEGER(Ldrh);
-      break;
-    case kAtomicLoadWord32:
-      __ Ldr(i.OutputRegister32(),
-             MemOperand(i.InputRegister(0), i.InputRegister(1)));
-      __ Dmb(InnerShareable, BarrierAll);
       break;
   }
 }  // NOLINT(readability/fn_size)