Override date arithmetic adding support for fdbsql

We have to create our own extension, and make sure it's loaded after
the builtin one.

600 -> 600 examples
91 -> 89 failures
Retry not_committed autocommit statements

transactions still have to be handled by the user, but if it's a
single autocommit statement, we retry 10 times to get it to work

600 -> 600 examples
89 -> 66 failures
append WITH DATA for create table as select

We require WITH DATA or WITH NO DATA.

600 -> 600 examples
66 -> 66 failures