Performance testing of final Audit log buffering patch

Please do a performance test of the bb-12.0-mdev-34680-hf branch (final commit 1563988ae61ee32d6cad48252e7a37e3b9011026) to;
1) Validate that the Benchmarking numbers at the top of MDEV-34680 are still valid and that there is thus continued merit to have the feature.
2) Validate that there are no unexpected slowdowns on busy servers (i.e. many read/write threads operating).
Ref MDEV-37089 for an example of what was seen during testing.

Also please note the related discussion in TODO-5095.