There were several issues on how big GTID_EXECUTED sets were handled
on Group Replication pipeline, in particular when GTID_EXECUTED size
exceeded the 65535 characters length. The issues were:
  1) snapshot_version length computation was incorrectly limited to
     65535 characters length on Transaction_context_log_event;
  2) snapshot_version contained on certification info, which is
     serialized on View_change_log_event, was incorrectly limited to
     65535 characters length;
  3) internal interface between Group Replication plugin and server
     was incorrectly limiting GTID_EXECUTED to 65535 characters
     length.
  4) Column Transactions_committed_all_members column on
     performance_schema.replication_group_member_stats was limited
     to 65535 characters length.

This patch fixes the 4 above issues. Since issue 2) requires the
change of the serialization of View_change_log_event, this patch
makes Group Replication version 0.6.0 incompatible with the previous
ones. Incompatibility rules were added and also a test (with
simulated versions) to validate them.