[crankshaft] Remove the useless HCallStub instruction.

src/crankshaft/mips64/lithium-mips64.h

Index: src/crankshaft/mips64/lithium-mips64.h
diff --git a/src/crankshaft/mips64/lithium-mips64.h b/src/crankshaft/mips64/lithium-mips64.h
index 30d4f332609b6b27250850a3a8d57b14cfb17544..3f5f0c6c2da58b0ee0e24cc5e8d8836af0f84a6e 100644
--- a/src/crankshaft/mips64/lithium-mips64.h
+++ b/src/crankshaft/mips64/lithium-mips64.h
@@ -37,7 +37,6 @@ class LCodeGen;
   V(CallFunction)                            \
   V(CallNewArray)                            \
   V(CallRuntime)                             \
-  V(CallStub)                                \
   V(CheckArrayBufferNotNeutered)             \
   V(CheckInstanceType)                       \
   V(CheckMaps)                               \
@@ -458,19 +457,6 @@ class LParameter final : public LTemplateInstruction<1, 0, 0> {
 };
 
 
-class LCallStub final : public LTemplateInstruction<1, 1, 0> {
- public:
-  explicit LCallStub(LOperand* context) {
-    inputs_[0] = context;
-  }
-
-  LOperand* context() { return inputs_[0]; }
-
-  DECLARE_CONCRETE_INSTRUCTION(CallStub, "call-stub")
-  DECLARE_HYDROGEN_ACCESSOR(CallStub)
-};
-
-
 class LUnknownOSRValue final : public LTemplateInstruction<1, 0, 0> {
  public:
   bool HasInterestingComment(LCodeGen* gen) const override { return false; }