[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 dc6c52c3d117bc7feb4f2a76de0b1a2fe8067029..5ae6f4e4d956a5e280a3c79d78d60126ff102276 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -97,6 +97,8 @@ MachineRepresentation StackSlotRepresentationOf(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.
@@ -635,6 +637,8 @@ 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; }