Remove calls to prefersSequences()

[derrabus]

AbstractPlatform::prefersSequences() is deprecated and does not exist in DBAL 3. Let's not call it if it's not there.

[derrabus]

I've pushed a new attempt, this time with special handling for Postgres and Oracle. Those were the only DBAL platforms that preferred sequences.

Theoretically, this would still be a breaking change, if someone used a custom DBAL driver implementation (is this a thing?) that supports sequences and identity columns and prefers sequences.

[greg0ire]

Theoretically, this would still be a breaking change, if someone used a custom DBAL driver implementation (is this a thing?) that supports sequences and identity columns and prefers sequences.

Thanks for mentioning that, it sounds pretty unlikely.

[morozov]

Since there's an ongoing discussion in #8893, let's agree on something there first to make sure the changes here correspond to the agreement or explicitly agree that the discussion shouldn't hold the merge. Except for #8870 (comment), looks good to me.

[greg0ire]

I'd say #8893 shouldn't hold the merge, these problems look independent to me.

[greg0ire]

Thanks @derrabus !