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

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index dba3d9b2309b5085e623125173bde7e28b8fdeaf..dd99e89296c28ebb1ce17504f112fc467fd96a6e 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -2024,14 +2024,6 @@
        g.UseRegister(left), g.Use(right));
 }
 
-void InstructionSelector::VisitAtomicLoad(Node* node) {
-  LoadRepresentation load_rep = LoadRepresentationOf(node->op());
-  DCHECK(load_rep.representation() == MachineRepresentation::kWord8 ||
-         load_rep.representation() == MachineRepresentation::kWord16 ||
-         load_rep.representation() == MachineRepresentation::kWord32);
-  USE(load_rep);
-  VisitLoad(node);
-}
 
 // static
 MachineOperatorBuilder::Flags