Add MariaDB support for --move-tables mode

[ericyan]

Description

This PR adds MariaDB coverage and compatibility support for --move-tables mode:

• Adds MariaDB 10.5, 10.6, 10.11, 11.4, and 11.8 to the move-tables CI matrix.
• Uses MariaDB’s @@global.gtid_binlog_pos to capture the post-cutover drain coordinate when running with MariaDB.
• Makes the generated-columns move-tables fixture portable by removing MySQL-only NOT NULL annotations from generated columns.
• Keeps move-tables independent of the standard metadata-lock instrumentation check, because its cutover is a source-primary RENAME TABLE followed by a drain to the captured GTID; it never invokes atomicCutOver(), AtomicCutOverMagicLock, or ExpectMetadataLock.

In case this PR introduced Go code changes:

• contributed code is using same conventions as original code
• script/cibuild returns with no formatting errors, build errors or unit test errors.

[Copilot]

Pull request overview

Adds MariaDB compatibility and CI coverage for move-tables migrations.

Changes:

• Adds MariaDB images and replication setup.
• Uses MariaDB-specific GTID coordinates during cutover and resume.
• Makes fixtures and metadata-lock checks compatible with MariaDB.

Show a summary per file

File	Description
.github/workflows/move-tables-tests.yml	Expands the database test matrix.
script/docker-gh-ost-move-tables-tests	Configures MySQL/MariaDB containers and replication.
localtests/docker-compose-move-tables.yml	Accepts engine-specific server options.
localtests/move-tables-test.sh	Handles MariaDB GTID verification.
localtests/move-tables/generated-columns/create.sql	Makes generated columns portable.
go/logic/migrator.go	Selects the correct drain GTID variable and skips irrelevant metadata-lock checks.
go/logic/applier.go	Restores the source GTID flavor when resuming.
go/logic/migrator_move_tables_cutover_test.go	Tests GTID variable selection.

Review details

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• Files reviewed: 8/8 changed files
• Comments generated: 1
• Review effort level: Balanced

[Copilot]

Review details

• Files reviewed: 9/9 changed files
• Comments generated: 0 new
• Review effort level: Balanced