Fix randomly failing service_domain_db tests

[chrzaszcz]

For parallel tests, init/end should be done per group, not per TC.

[codecov]

Codecov Report

Merging #3181 (73cc11c) into master (de27b3f) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3181      +/-   ##
==========================================
- Coverage   80.27%   80.25%   -0.02%     
==========================================
  Files         396      396              
  Lines       32327    32327              
==========================================
- Hits        25950    25945       -5     
- Misses       6377     6382       +5     

Impacted Files	Coverage Δ
src/mod_roster_riak.erl	81.53% <0.00%> (-15.39%)	⬇️
src/jingle_sip/mod_jingle_sip_backend.erl	80.00% <0.00%> (-5.00%)	⬇️
src/domain/mongoose_domain_core.erl	88.09% <0.00%> (-1.20%)	⬇️
src/wpool/mongoose_wpool.erl	84.00% <0.00%> (-1.00%)	⬇️
src/muc_light/mod_muc_light_utils.erl	90.00% <0.00%> (-1.00%)	⬇️
src/inbox/mod_inbox_rdbms.erl	92.50% <0.00%> (-0.63%)	⬇️
src/mod_muc.erl	74.77% <0.00%> (-0.23%)	⬇️
src/mod_muc_log.erl	77.77% <0.00%> (ø)
src/ejabberd_c2s.erl	89.27% <0.00%> (+0.07%)	⬆️
src/mod_muc_room.erl	77.10% <0.00%> (+0.17%)	⬆️
... and 3 more

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[mongoose-im]

small_tests_21_3 / small_tests / 73cc11c
Reports root / small

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small_tests_22 / small_tests / 73cc11c
Reports root / small

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dynamic_domains / pgsql_mnesia / 73cc11c
Reports root/ big
OK: 1585 / Failed: 0 / User-skipped: 111 / Auto-skipped: 0

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small_tests_23 / small_tests / 73cc11c
Reports root / small

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ldap_mnesia_22 / ldap_mnesia / 73cc11c
Reports root/ big
OK: 1514 / Failed: 0 / User-skipped: 359 / Auto-skipped: 0

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ldap_mnesia_21 / ldap_mnesia / 73cc11c
Reports root/ big
OK: 1514 / Failed: 0 / User-skipped: 359 / Auto-skipped: 0

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internal_mnesia / internal_mnesia / 73cc11c
Reports root/ big
OK: 1587 / Failed: 0 / User-skipped: 286 / Auto-skipped: 0

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ldap_mnesia_23 / ldap_mnesia / 73cc11c
Reports root/ big
OK: 1514 / Failed: 0 / User-skipped: 359 / Auto-skipped: 0

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pgsql_mnesia / pgsql_mnesia / 73cc11c
Reports root/ big
OK: 3084 / Failed: 0 / User-skipped: 184 / Auto-skipped: 0

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elasticsearch_and_cassandra / elasticsearch_and_cassandra_mnesia / 73cc11c
Reports root/ big
OK: 1890 / Failed: 0 / User-skipped: 282 / Auto-skipped: 0

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mysql_redis / mysql_redis / 73cc11c
Reports root/ big
OK: 3067 / Failed: 0 / User-skipped: 201 / Auto-skipped: 0

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mssql_mnesia / odbc_mssql_mnesia / 73cc11c
Reports root/ big
OK: 3084 / Failed: 0 / User-skipped: 184 / Auto-skipped: 0

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riak_mnesia / riak_mnesia / 73cc11c
Reports root/ big
OK: 1737 / Failed: 0 / User-skipped: 285 / Auto-skipped: 0

[arcusfelis]

ok