Merge lowerCall and lowerRet between x86 and x64

src/IceTargetLoweringX8632.h

 //===- subzero/src/IceTargetLoweringX8632.h - x86-32 lowering ---*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 40 matching lines @@
 protected:
   void _add_sp(Operand *Adjustment);
   void _mov_sp(Operand *NewValue);
   Traits::X86OperandMem *_sandbox_mem_reference(X86OperandMem *) {
     llvm::report_fatal_error("sandbox mem reference for x86-32.");
   }
   void _sub_sp(Operand *Adjustment);
 
   void initSandbox() {}
   void lowerIndirectJump(Variable *JumpTarget);
-  void lowerCall(const InstCall *Instr) override;
-  void lowerArguments() override;
-  void lowerRet(const InstRet *Inst) override;
+  Inst *emitCallToTarget(Operand *CallTarget, Variable *ReturnReg) override;
+  Variable *moveReturnValueToRegister(Operand *Value, Type ReturnType) override;
   void addProlog(CfgNode *Node) override;
   void addEpilog(CfgNode *Node) override;
 
 private:
   ENABLE_MAKE_UNIQUE;
   friend class X8632::TargetX86Base<X8632::Traits>;
 
   Operand *createNaClReadTPSrcOperand() {
     Constant *Zero = Ctx->getConstantZero(IceType_i32);
     return Traits::X86OperandMem::create(Func, IceType_i32, nullptr, Zero,
@@ skipping 42 matching lines @@
   explicit TargetHeaderX8632(GlobalContext *Ctx);
 
 private:
   ~TargetHeaderX8632() = default;
 };
 
 } // end of namespace X8632
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX8632_H