Use performance schema `processlist` table

[bgrainger]

The ProcessList schema (used by MySqlConnection.GetSchema("ProcessList")) uses INFORMATION_SCHEMA.PROCESSLIST.

From MySQL Server 8.0, this is deprecated:

INFORMATION_SCHEMA.PROCESSLIST is deprecated and subject to removal in a future MySQL release. As such, the implementation of SHOW PROCESSLIST which uses this table is also deprecated. It is recommended to use the Performance Schema implementation of PROCESSLIST instead.

Evaluate cross-server compatibility (e.g., this seems to be supported in MariaDB 10.5 and possibly earlier but may be disabled by default) and use the new table on servers that support it.