[midend]优化中端框架，移除无用旧代码，ignore格式文件

src/include/Reg2Mem.h

@@ -1,22 +0,0 @@
-#pragma once
-
-#include "IR.h"
-#include "IRBuilder.h"
-#include "SysYIROptUtils.h"
-
-namespace sysy {
-/**
- * Reg2Mem(后端未做phi指令翻译)
- */
-class Reg2Mem {
-private:
-  Module *pModule;
-  IRBuilder *pBuilder;
-
-public:
-  Reg2Mem(Module *pMoudle, IRBuilder *pBuilder) : pModule(pMoudle), pBuilder(pBuilder) {}
-
-  void DeletePhiInst();
-};
-
-} // namespace sysy