[crankshaft] Remove the useless HCallStub instruction.

src/crankshaft/hydrogen-instructions.h

Index: src/crankshaft/hydrogen-instructions.h
diff --git a/src/crankshaft/hydrogen-instructions.h b/src/crankshaft/hydrogen-instructions.h
index 6fed00faaad6286ddbc42bdb73d6a70f04c71b6d..ec281bc6dde504cd86d6bc0f7c7f7bba265e1060 100644
--- a/src/crankshaft/hydrogen-instructions.h
+++ b/src/crankshaft/hydrogen-instructions.h
@@ -64,7 +64,6 @@ class LChunkBuilder;
   V(CallFunction)                             \
   V(CallNewArray)                             \
   V(CallRuntime)                              \
-  V(CallStub)                                 \
   V(CapturedObject)                           \
   V(Change)                                   \
   V(CheckArrayBufferNotNeutered)              \
@@ -5235,27 +5234,6 @@ class HParameter final : public HTemplateInstruction<0> {
 };
 
 
-class HCallStub final : public HUnaryCall {
- public:
-  DECLARE_INSTRUCTION_WITH_CONTEXT_FACTORY_P2(HCallStub, CodeStub::Major, int);
-  CodeStub::Major major_key() { return major_key_; }
-
-  HValue* context() { return value(); }
-
-  std::ostream& PrintDataTo(std::ostream& os) const override;  // NOLINT
-
-  DECLARE_CONCRETE_INSTRUCTION(CallStub)
-
- private:
-  HCallStub(HValue* context, CodeStub::Major major_key, int argument_count)
-      : HUnaryCall(context, argument_count),
-        major_key_(major_key) {
-  }
-
-  CodeStub::Major major_key_;
-};
-
-
 class HUnknownOSRValue final : public HTemplateInstruction<0> {
  public:
   DECLARE_INSTRUCTION_FACTORY_P2(HUnknownOSRValue, HEnvironment*, int);