Fixes https://github.com/spring-projects/spring-integration/issues/3683
If a transaction is already active while `JdbcLockRegistry` uses
`DefaultLockRepository` to acquire/release a lock, the repository
must execute SQL queries in a separate transaction to prevent
problems with blocking, deadlocking etc.
It also allows to properly follow transaction isolation level that
is set on some methods of `DefaultLockRepository`.
Previously all methods of DefaultLockRepository supported the current
transaction if there are any. Now all methods will always create new
transaction on each call.
* Change tests to be more unit-ish
* Change `@since` for the `DefaultLockRepositoryTests` to `5.3.10`
**Cherry-pick to `5.4.x` & `5.3.x`**
8b619bb3a3