MDEV-30536: Fix Galera bulk insert optimization MTR test

[denis-protivensky]

• [x] The Jira issue number for this PR is: MDEV-30536

Description

After closing https://github.com/codership/galera-bugs/issues/947, Galera now correctly certifies table-level keys, which made bulk insert work again.

Release Notes

Requires Galera 26.4.19

How can this PR be tested?

The corresponding MTR test is made deterministic and re-enabled.

Basing the PR against the correct MariaDB version

• [ ] This is a new feature or a refactoring, and the PR is based against the latest MariaDB development branch.
• [x] This is a bug fix, and the PR is based against the earliest maintained branch in which the bug can be reproduced.

PR quality check

• [x] I checked the CODING_STANDARDS.md file and my PR conforms to this where appropriate.
• [x] For any trivial modifications to the PR, I am ok with the reviewer making the changes themselves.