test-run: fragile list cause to fail runs with 'reproduce' flag

Tarantool version:

OS version:

Bug description:
test-run tool sets tests from fragile list in suite.ini file to 'fragile' standalone suite, is cause the 'reproduce' flag to fail on its use, like:

./test-run.py --reproduce box.list.yaml
Started ./test-run.py --reproduce box.list.yaml
Running in parallel with 2 workers

Traceback (most recent call last):
  File "./test-run.py", line 218, in <module>
    status = main_parallel()
  File "./test-run.py", line 133, in main_parallel
    res = main_loop_parallel()
  File "./test-run.py", line 88, in main_loop_parallel
    task_groups = lib.worker.reproduce_task_groups(task_groups)
  File "/home/vagrant/tnt/test-run/lib/worker.py", line 118, in reproduce_task_groups
    '[reproduce] Given tests contained by different suites')
ValueError: [reproduce] Given tests contained by different suites

Steps to reproduce:

Optional (but very desirable):

• coredump
• backtrace
• netstat