[Compatibility]: Different behavior on locking read under snapshot isolation level

[xiexiaoy]

With the snapshot isolation level

InnoDB: Locking read always returns the latest version, behaves as read-committed semantics.
EloqSQL: Locking read always returns the nearest version, behaves as repeatable-read semantics.

The difference may cause difficulties in leveraging existing tests.

Locking read:

• select ... for share.
• select ... for update.
• update ... where ...