test: engine/hints fails sporadically

[kyukhin]

Tarantool version: 2.2.x

OS version: Linux

Bug description:
The test fails sporadically

Steps to reproduce:

./test-run.py --builddir ../../bld -j 48 --force --long engine/hints engine/hints engine/hints engine/hints

005] Test failed! Result content mismatch:                                                                                                                                                                          
[008] engine/hints.test.lua                           memtx           [ pass ]                                                                                                                                       
[005] --- engine/hints.result   Wed Mar 27 16:03:59 2019                                                                                                                                                             
[005] +++ engine/hints.reject   Wed Mar 27 16:12:41 2019                                                                                                                                                             
[005] @@ -77,6 +77,7 @@                                                                                                                                                                                              
[005]    - [1152921504606846976]                                                                                                                                                                                     
[005]    - [2305843009213693952]                                                                                                                                                                                     
[005]    - [4611686018427387904]                                                                                                                                                                                     
[005] +  - [9223372036854775807]                                                                                                                                                                                     
[005]    - [9223372036854775808]                                                                                                                                                                                     
[005]  ...                                                                                                                                                                                                           
[005]  i1:alter{parts = {1, 'number'}}                                                                                                                                                                               
[005] @@ -98,6 +99,7 @@                                                                                                                                                                                              
[005]    - [1152921504606846976]                                                                                                                                                                                     
[005]    - [2305843009213693952]                                                                                                                                                                                     
[005]    - [4611686018427387904]                                                                                                                                                                                     
[005] +  - [9223372036854775807]                                                                                                                                                                                     
[005]    - [9223372036854775808]                                                                                                                                                                                     
[005]    - [1.844674407371e+19]                                                                                                                                                                                      
[005]  ...                                                                                                                                                                                                           
[005]

[kshcherbatov]

The problem is not connected with hints:
Steps to reproduce: call insert_values in console multiple time, e.g.

ffi = require('ffi')
function insert_values(type)
        local x = 54
        while (x <= 64) do
                local val = ffi.new(type, 2^x-1)
                print(val)
                x = x + 1
        end
end;
insert_values('int64_t')

tarantool> insert_values('int64_t')
18014398509481984LL
36028797018963968LL
72057594037927936LL
144115188075855872LL
288230376151711744LL
576460752303423488LL
1152921504606846976LL
2305843009213693952LL
4611686018427387904LL
-9223372036854775808LL
-9223372036854775808LL
---
...

tarantool> insert_values('int64_t')
18014398509481984LL
36028797018963967LL
72057594037927935LL
144115188075855871LL
288230376151711743LL
576460752303423487LL
1152921504606846975LL
2305843009213693951LL
4611686018427387903LL
9223372036854775807LL
9223372036854775807LL

[Totktonada]

It gives stable results after jit.off(). But anyway it is signed type overflow (undefined behaviour) and need to be fixed.