reformat source code

according to code styles, 'AccessModifierOffset' should be -2.

src/sql/engine/expr/ob_expr_to_single_byte.h

@@ -18,13 +18,13 @@ namespace oceanbase {
 namespace sql {
 
 class ObExprToSingleByte : public ObFuncExprOperator {
-  public:
+public:
   explicit ObExprToSingleByte(common::ObIAllocator& alloc);
   virtual ~ObExprToSingleByte();
   int calc_result_type1(ObExprResType& type, ObExprResType& type1, common::ObExprTypeCtx& type_ctx) const;
   int calc_result1(common::ObObj& result, const common::ObObj& obj, common::ObExprCtx& expr_ctx) const;
 
-  private:
+private:
   DISALLOW_COPY_AND_ASSIGN(ObExprToSingleByte);
 };