test: filter replication/skip_conflict_row output

Found that test replication/skip_conflict_row.test.lua fails with
output message in results file:

  [035] @@ -139,7 +139,19 @@
  [035]  -- applier is not in follow state
  [035]  test_run:wait_upstream(1, {status = 'stopped', message_re = "Duplicate key exists in unique index 'primary' in space 'test'"})
  [035]  ---
  [035] -- true
  [035] +- false
  [035] +- id: 1
  [035] +  uuid: f2084d3c-93f2-4267-925f-015df034d0a5
  [035] +  lsn: 553
  [035] +  upstream:
  [035] +    status: follow
  [035] +    idle: 0.0024020448327065
  [035] +    peer: unix/:/builds/4BUsapPU/0/tarantool/tarantool/test/var/035_replication/master.socket-iproto
  [035] +    lag: 0.0046234130859375
  [035] +  downstream:
  [035] +    status: follow
  [035] +    idle: 0.086121961474419
  [035] +    vclock: {2: 3, 1: 553}
  [035]  ...
  [035]  --
  [035]  -- gh-3977: check that NOP is written instead of conflicting row.

Test could not be restarted with checksum because of changing values
like UUID on each fail. It happend because test-run uses internal
chain of functions wait_upstream() -> gen_box_info_replication_cond()
which returns instance information on its fails. To avoid of it this
output was redirected to log file instead of results file.