test: flaky replication/anon.test.lua test

Found flaky issues multi running replication/anon.test.lua test
on the single worker:

 [007] --- replication/anon.result	Fri Jun  5 09:02:25 2020
 [007] +++ replication/anon.reject	Mon Jun  8 01:19:37 2020
 [007] @@ -55,7 +55,7 @@
 [007]
 [007]  box.info.status
 [007]   | ---
 [007] - | - running
 [007] + | - orphan
 [007]   | ...
 [007]  box.info.id
 [007]   | ---

 [094] --- replication/anon.result       Sat Jun 20 06:02:43 2020
 [094] +++ replication/anon.reject       Tue Jun 23 19:35:28 2020
 [094] @@ -154,7 +154,7 @@
 [094]  -- Test box.info.replication_anon.
 [094]  box.info.replication_anon
 [094]   | ---
 [094] - | - count: 1
 [094] + | - count: 2
 [094]   | ...
 [094]  #box.info.replication_anon()
 [094]   | ---
 [094]

It happend because replications may stay active from the previous
runs on the common tarantool instance at the test-run worker. To
avoid of it added restarting of the tarantool instance at the very
start of the test.

Closes #5058