sql: use optimizer cost perturbation and disable rule settings for metamorphic testing

[rytaft]

We created session settings testing_optimizer_cost_perturbation and testing_optimizer_disable_rule_probability to use for the randomized tests costfuzz and unoptimized_query_oracle. We should also use them as metamorphic constants that are used with metamorphic testing. This will give us more test coverage.

Jira issue: CRDB-22542

[rytaft]

Since these flags will make plans slow, we should probably not enable these flags on SQLite.

[yuzefovich]

I looked into this in #94936, but there were quite a few failures and I since lost the context on it, so unassigning myself and putting into 23.2 bucket.