[turbofan] Remove dead code from Diamond class.

src/compiler/diamond.h

Index: src/compiler/diamond.h
diff --git a/src/compiler/diamond.h b/src/compiler/diamond.h
index e6208e40aced7ddddb1e7029281ad8d18c31d218..e7e0a2c32d584a80ad688ccd9e74d39316065b2a 100644
--- a/src/compiler/diamond.h
+++ b/src/compiler/diamond.h
@@ -8,7 +8,6 @@
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/node.h"
-#include "src/compiler/node-properties.h"
 
 namespace v8 {
 namespace internal {
@@ -57,28 +56,10 @@ struct Diamond {
   Node* EffectPhi(Node* tv, Node* fv) {
     return graph->NewNode(common->EffectPhi(2), tv, fv, merge);
   }
-
-  void OverwriteWithPhi(Node* node, MachineType machine_type, Node* tv,
-                        Node* fv) {
-    DCHECK(node->InputCount() >= 3);
-    node->ReplaceInput(0, tv);
-    node->ReplaceInput(1, fv);
-    node->ReplaceInput(2, merge);
-    node->TrimInputCount(3);
-    NodeProperties::ChangeOp(node, common->Phi(machine_type, 2));
-  }
-
-  void OverwriteWithEffectPhi(Node* node, Node* te, Node* fe) {
-    DCHECK(node->InputCount() >= 3);
-    node->ReplaceInput(0, te);
-    node->ReplaceInput(1, fe);
-    node->ReplaceInput(2, merge);
-    node->TrimInputCount(3);
-    NodeProperties::ChangeOp(node, common->EffectPhi(2));
-  }
 };
-}
-}
-}  // namespace v8::internal::compiler
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
 
 #endif  // V8_COMPILER_DIAMOND_H_