sql: meta issue for SQL Queries testing

[rytaft]

This issue will serve as the meta-issue for our upcoming testing sprint. Please add ideas or links to other relevant issues.

• sql: add unique constraint checks to SCRUB #73632
• randgen: add PARTITION BY clauses to random table generation #73920
• logictestccl: add gateway region as metamorphic test variable #73970
• multiregionccl: add mutations to TestMultiRegionDataDriven #73971
• ccl: run CCL logictests in a mode with locality optimized search disabled #73633
• sql: finish implementing optimizer-specific nightly tests #62901
• Add more string family test coverage to SQL fuzz testing #77311
• rowenc: write unit tests for NeededColumnFamilyIDs #76623
• sql: DefaultBatchBytesLimit and ParallelScanResultThreshold should be metamorphic constants #75468
• sql: randomize distsql_workmem value more #77645
• Update SQLancer to use CRDB v21.2
• More thorough testing of prepared statements (e.g., automatically turn logic tests into prepared statements)
• Explore how we could do some testing with the new QoS levels. in the past, Andrew suggested we could run an OLAP workload at background level and an OLTP workload at critical level
• Finish sql: enable sqllogictest bigtest select5.test #76396
• Investigate whether index recommendations work with partitioned and hash-sharded tables
• Investigate sql: interface conversion: coldata.Column is coldata.Int64s, not coldata.Int32s #76969
• Investigate timeouts such as roachtest: tpchvec/perf_no_stats failed #78157, roachtest: tpcdsvec failed #78128
• sql/logictest: reenable crdb_test randomizations in TestSqlLiteLogic #58089
• roachtest: create a test to validate query results by disabling the optimizer and vectorized engine #83090
• kvstreamer: randomized testing with a simple table schema #81806

Jira issue: CRDB-13591