MDEV-33133: MDL conflict handling code should skip BF-aborted trxs

[denis-protivensky]

• The Jira issue number for this PR is: MDEV-33133

Description

It's possible that MDL conflict handling code is called more than once for a transaction when:

• it holds more than one conflicting MDL lock
• reschedule_waiters() is executed, which results in repeated attempts to BF-abort already aborted transaction.
  In such situations, it might be that BF-aborting logic sees a partially rolled back transaction and erroneously decides on future actions for such a transaction.

The specific situation tested and fixed is when a SR transaction applied in the node gets BF-aborted by a started TOI operation. It's then caught with the server transaction already rolled back, but with no MDL locks yet released. This caused wrong state detection for such a transaction during repeated MDL conflict handling code execution.

How can this PR be tested?

MTR test is provided.

Basing the PR against the correct MariaDB version

• This is a new feature and the PR is based against the latest MariaDB development branch.
• 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

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

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