[refactor] replace boost smart ptr with stl (#6856)

1. replace all boost::shared_ptr to std::shared_ptr
2. replace all boost::scopted_ptr to std::unique_ptr
3. replace all boost::scoped_array to std::unique<T[]>
4. replace all boost:thread to std::thread

be/src/exprs/arithmetic_expr.cpp

@@ -43,9 +43,9 @@ Expr* ArithmeticExpr::from_thrift(const TExprNode& node) {
     case TExprOpcode::BITNOT:
         return new BitNotExpr(node);
     default:
-        return NULL;
+        return nullptr;
     }
-    return NULL;
+    return nullptr;
 }
 
 #define BINARY_OP_CHECK_ZERO_FN(TYPE, CLASS, FN, OP)      \