asan: leak unit/swim.test:swim_test_encryption

Found leak issue:

  [001] +==41031==ERROR: LeakSanitizer: detected memory leaks
  [001] +
  [001] +Direct leak of 96 byte(s) in 2 object(s) allocated from:
  [001] +    #0 0x4d8e53 in __interceptor_malloc (/tnt/test/unit/swim.test+0x4d8e53)
  [001] +    #1 0x53560f in crypto_codec_new /source/src/lib/crypto/crypto.c:239:51
  [001] +    #2 0x5299c4 in swim_scheduler_set_codec /source/src/lib/swim/swim_io.c:700:30
  [001] +    #3 0x511fe6 in swim_cluster_set_codec /source/test/unit/swim_test_utils.c:251:2
  [001] +    #4 0x50b3ae in swim_test_encryption /source/test/unit/swim.c:767:2
  [001] +    #5 0x50b3ae in main_f /source/test/unit/swim.c:1123
  [001] +    #6 0x544a3b in fiber_loop /source/src/lib/core/fiber.c:869:18
  [001] +    #7 0x5a13d0 in coro_init /source/third_party/coro/coro.c:110:3
  [001] +
  [001] +SUMMARY: AddressSanitizer: 96 byte(s) leaked in 2 allocation(s).

Prepared minimal issue reproducer:

  static void
  swim_test_encryption(void)
  {
          swim_start_test(3);
          struct swim_cluster *cluster = swim_cluster_new(2);
          swim_cluster_set_codec(cluster, CRYPTO_ALGO_AES128, CRYPTO_MODE_CBC,
                                 "1234567812345678", CRYPTO_AES128_KEY_SIZE);
          swim_cluster_delete(cluster);
          swim_finish_test();
  }

Found that memory allocation for codec creation at crypto_codec_new()
using swim_cluster_set_codec() was not any freed at the test. Added
crypto_codec_delete() in swim_scheduler_destroy() function for it.

After this fix removed susspencion on memory leak for unit/swim.test.

Closes #5283

Reviewed-by: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>

Co-authored-by: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>