lua output: nested tables are stripped

[olegrok]

Tarantool version: 2.3.0-136-gaf9ef2115

tarantool> \set output lua
true;
tarantool> a = {1, 2, 3}
;
tarantool> a
{1, 2, 3};
tarantool> b = {a = a, b = {a, a, a}}
;
tarantool> b
{a = {1, 2, 3}, b = {nil, nil, nil}};

Expected {a = {1, 2, 3}, b = {{1, 2, 3}, {1, 2, 3}, {1, 2, 3}}};

reported by @filonenko-mikhail