Merge lowerCall and lowerRet between x86 and x64

src/IceTargetLoweringX8632.h

Index: src/IceTargetLoweringX8632.h
diff --git a/src/IceTargetLoweringX8632.h b/src/IceTargetLoweringX8632.h
index 1f8e4a702be58667b2f9537f63f8923165d6300a..39ba6083897a41f95076c35c8f62255f60ad4a48 100644
--- a/src/IceTargetLoweringX8632.h
+++ b/src/IceTargetLoweringX8632.h
@@ -58,9 +58,8 @@ protected:
 
   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;