txn:make transaction amend fully compatible with binlog

[cfzjywxk]

Feature Request

Is your feature request related to a problem? Please describe:

The transaction amend introduces some changes such as:

without amend:   schemaVerTS < startTS < commitTS
with amend:      startTS < schemaVerTS < amendTS < commitTS

The commitTS is NOT guanranteed to be greater than the latest valid schema version, which means the amended transaction may commit after the concurrent DDLs but using a previous schema version.

The Binlog will replay the SQLs according to the transaction commitTS, now the binlog may replay a transaction committed using latest schema version while the transaction content is generated using the older schema version, which may change the effect of replayed SQLs thus causing inconsistency bettwen upstream and downstream.

There are some known issues listed below:
#20909 Amend on the add unique index DDL will confuse the Binlog drainer doing replay.
#20773 Amend on the add column DDL will make drainer failure doing decode.It's being solved.

Describe the feature you'd like:

Try to make the amended transaction fully compatible with Binlog, we may need to change the transaction content or replay mode in Binlog to process the amended transaction properly.

Describe alternatives you've considered:

• Make the amenede transaction memory buffer compatible with the latest schema version.
• Add support for amended transaction replay in Binlog.

Teachability, Documentation, Adoption, Migration Strategy: