test: flaky box/* tests on error: Role 'role' is not found

[avtikhon]

Tarantool version:
Tarantool 2.7.0-49-g9f5d5003d
Target: Darwin-x86_64-RelWithDebInfo
Build options: cmake . -DCMAKE_INSTALL_PREFIX=/usr/local -DENABLE_BACKTRACE=ON
Compiler: /Library/Developer/CommandLineTools/usr/bin/cc /Library/Developer/CommandLineTools/usr/bin/c++
C_FLAGS: -Wno-unknown-pragmas -fexceptions -funwind-tables -fno-omit-frame-pointer -fno-stack-protector -fno-common -msse2 -std=c11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts -Wno-gnu-alignof-expression -Werror
CXX_FLAGS: -Wno-unknown-pragmas -fexceptions -funwind-tables -fno-omit-frame-pointer -fno-stack-protector -fno-common -msse2 -std=c++11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts -Wno-invalid-offsetof -Wno-gnu-alignof-expression -Werror

OS version:
OSX 15

Bug description:
https://gitlab.com/tarantool/tarantool/-/jobs/866414533#L4044

artifacts.zip

results file checksum: 33e685a1e7a346ceb3749fa0bd0528a2

[045] --- box/ddl_call_twice_gh-2336.result	Thu Nov 12 16:13:40 2020
[045] +++ /tmp/tnt/rejects/box/ddl_call_twice_gh-2336.reject	Mon Nov 23 13:46:51 2020
[045] @@ -1,44 +1,4 @@
[045]  -- test-run result file version 2
[045] --- tarantool/tarantool#2336 crash if format called twice during snapshot
[045] -fiber = require'fiber'
[045] - | ---
[045] - | ...
[045] -
[045] -space = box.schema.space.create('test_format')
[045] - | ---
[045] - | ...
[045] -_ = space:create_index('pk', { parts = { 1,'str' }})
[045] - | ---
[045] - | ...
[045] -space:format({{ name ="key"; type = "string" }, { name ="dataAB"; type = "string" }})
[045] - | ---
[045] - | ...
[045] -str = string.rep("t",1024)
[045] - | ---
[045] - | ...
[045] -for i = 1, 10000 do space:insert{tostring(i), str} end
[045] - | ---
[045] - | ...
[045] -ch = fiber.channel(3)
[045] - | ---
[045] - | ...
[045] -_ = fiber.create(function() fiber.yield() box.snapshot() ch:put(true) end)
[045] - | ---
[045] - | ...
[045] -format = {{name ="key"; type = "string"}, {name ="data"; type = "string"}}
[045] - | ---
[045] - | ...
[045] -for i = 1, 2 do fiber.create(function() fiber.yield() space:format(format) ch:put(true) end) end
[045] - | ---
[045] - | ...
[045] -
[045] -{ch:get(), ch:get(), ch:get()}
[045] - | ---
[045] - | - - true
[045] - |   - true
[045] - |   - true
[045] - | ...
[045] -
[045] -space:drop()
[045] - | ---
[045] - | ...
[045] +---
[045] +- error: Role 'role' is not found
[045] +...
[045] 

Steps to reproduce:

Optional (but very desirable):

• coredump
• backtrace
• netstat