sql: recognize the `[NOT] DEFERRABLE` `SET TRANSACTION` arguments

[jseldess]

PR: cockroachdb/cockroach#53435

From release notes:

CockroachDB now recognizes the NOT DEFERRABLE and DEFERRABLE arguments to SET TRANSACTION. Note that the DEFERRABLE argument is still unimplemented. [#53435][#53435] {% comment %}doc{% endcomment %}