CB failures when using oracle mysql 8.0.22

several unittests fail when upgrading to oracle mysql 8.0.22

[  PASSED  ] 123 tests.
[  FAILED  ] 6 tests, listed below:
[  FAILED  ] MySqlConfigBackendDHCPv4Test.deleteSubnet4
[  FAILED  ] MySqlConfigBackendDHCPv4Test.deleteSharedNetwork4
[  FAILED  ] MySqlConfigBackendDHCPv4Test.getAllOptionDefs4
[  FAILED  ] MySqlConfigBackendDHCPv6Test.deleteSubnet6
[  FAILED  ] MySqlConfigBackendDHCPv6Test.deleteSharedNetwork6
[  FAILED  ] MySqlConfigBackendDHCPv6Test.getAllOptionDefs6

fount during sanity checks on 1.9.1 and 1.9.2 (28 oct 2020)

package release date for Ubuntu 20.04:

| 8.0.22-0ubuntu0.20.04.2 | security, updates (main) | 2020-10-27 |

[ RUN      ] MySqlConfigBackendDHCPv4Test.deleteSubnet4
mysql_cb_dhcp4_unittest.cc:1738: Failure
Expected equality of these values:
  1
  deleted_count
    Which is: 2
Google Test trace:
mysql_cb_dhcp4_unittest.cc:1733: one server
mysql_cb_dhcp4_unittest.cc:1759: Failure
Expected equality of these values:
  1
  deleted_count
    Which is: 2
Google Test trace:
mysql_cb_dhcp4_unittest.cc:1754: one server
[  FAILED  ] MySqlConfigBackendDHCPv4Test.deleteSubnet4 (272 ms)
[ RUN      ] MySqlConfigBackendDHCPv4Test.deleteSharedNetwork4
mysql_cb_dhcp4_unittest.cc:2762: Failure
Expected equality of these values:
  1
  deleted_count
    Which is: 2
Google Test trace:
mysql_cb_dhcp4_unittest.cc:2756: one server
[  FAILED  ] MySqlConfigBackendDHCPv4Test.deleteSharedNetwork4 (200 ms)
[ RUN      ] MySqlConfigBackendDHCPv4Test.getAllOptionDefs4
mysql_cb_dhcp4_unittest.cc:505: Failure
Expected equality of these values:
  audit_entries_size_save + new_entries_num
    Which is: 3
  audit_entries_[tag].size()
    Which is: 2
dhcp4_option_def, 29, 0, 2020-Nov-25 11:33:39, 1174, option definition set
dhcp4_option_def, 29, 1, 2020-Nov-25 11:33:39, 1175, option definition set

Google Test trace:
mysql_cb_dhcp4_unittest.cc:3221: CREATE audit entry for the option defnition fish
mysql_cb_dhcp4_unittest.cc:505: Failure
Expected equality of these values:
  audit_entries_size_save + new_entries_num
    Which is: 3
  audit_entries_[tag].size()
    Which is: 2
dhcp4_option_def, 29, 0, 2020-Nov-25 11:33:39, 1174, option definition set
dhcp4_option_def, 29, 1, 2020-Nov-25 11:33:39, 1175, option definition set

Google Test trace:
mysql_cb_dhcp4_unittest.cc:3221: CREATE audit entry for the option defnition whale
mysql_cb_dhcp4_unittest.cc:3230: Failure
Expected equality of these values:
  test_option_defs_.size() - updates_num
    Which is: 3
  option_defs.size()
    Which is: 1
[  FAILED  ] MySqlConfigBackendDHCPv4Test.getAllOptionDefs4 (138 ms)
[ RUN      ] MySqlConfigBackendDHCPv6Test.deleteSubnet6
mysql_cb_dhcp6_unittest.cc:1748: Failure
Expected equality of these values:
  1
  deleted_count
    Which is: 2
Google Test trace:
mysql_cb_dhcp6_unittest.cc:1743: one server
mysql_cb_dhcp6_unittest.cc:1769: Failure
Expected equality of these values:
  1
  deleted_count
    Which is: 2
Google Test trace:
mysql_cb_dhcp6_unittest.cc:1764: one server
[  FAILED  ] MySqlConfigBackendDHCPv6Test.deleteSubnet6 (283 ms)
[ RUN      ] MySqlConfigBackendDHCPv6Test.deleteSharedNetwork6
mysql_cb_dhcp6_unittest.cc:2797: Failure
Expected equality of these values:
  1
  deleted_count
    Which is: 2
Google Test trace:
mysql_cb_dhcp6_unittest.cc:2791: one server
[  FAILED  ] MySqlConfigBackendDHCPv6Test.deleteSharedNetwork6 (159 ms)
[ RUN      ] MySqlConfigBackendDHCPv6Test.getAllOptionDefs6
mysql_cb_dhcp6_unittest.cc:552: Failure
Expected equality of these values:
  audit_entries_size_save + new_entries_num
    Which is: 3
  audit_entries_[tag].size()
    Which is: 2
dhcp6_option_def, 29, 0, 2020-Nov-25 11:33:49, 1236, option definition set
dhcp6_option_def, 29, 1, 2020-Nov-25 11:33:49, 1237, option definition set

Google Test trace:
mysql_cb_dhcp6_unittest.cc:3258: CREATE audit entry for the option definition fish
mysql_cb_dhcp6_unittest.cc:552: Failure
Expected equality of these values:
  audit_entries_size_save + new_entries_num
    Which is: 3
  audit_entries_[tag].size()
    Which is: 2
dhcp6_option_def, 29, 0, 2020-Nov-25 11:33:49, 1236, option definition set
dhcp6_option_def, 29, 1, 2020-Nov-25 11:33:49, 1237, option definition set

Google Test trace:
mysql_cb_dhcp6_unittest.cc:3258: CREATE audit entry for the option definition whale
mysql_cb_dhcp6_unittest.cc:3268: Failure
Expected equality of these values:
  test_option_defs_.size() - updates_num
    Which is: 3
  option_defs.size()
    Which is: 1
[  FAILED  ] MySqlConfigBackendDHCPv6Test.getAllOptionDefs6 (129 ms)