[Atomics] Make Atomics.exchange a builtin using TF

src/compiler/machine-operator.h

Index: src/compiler/machine-operator.h
diff --git a/src/compiler/machine-operator.h b/src/compiler/machine-operator.h
index aee27045fd9a1994822b6c736b8575feb3fc5687..217455cce1004c09996f8ebfb4d87d10ffcf1b86 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -97,6 +97,8 @@ int StackSlotSizeOf(Operator const* op);
 
 MachineRepresentation AtomicStoreRepresentationOf(Operator const* op);
 
+MachineType AtomicExchangeRepresentationOf(Operator const* op);
+
 // Interface for building machine-level operators. These operators are
 // machine-level but machine-independent and thus define a language suitable
 // for generating code to run on architectures such as ia32, x64, arm, etc.
@@ -618,6 +620,8 @@ class V8_EXPORT_PRIVATE MachineOperatorBuilder final
   const Operator* AtomicLoad(LoadRepresentation rep);
   // atomic-store [base + index], value
   const Operator* AtomicStore(MachineRepresentation rep);
+  // atomic-exchange [base + index], value
+  const Operator* AtomicExchange(MachineType rep);
 
   // Target machine word-size assumed by this builder.
   bool Is32() const { return word() == MachineRepresentation::kWord32; }