remove reranking and force rerankK=limit in diskann (sstable) searches. memtables unaffected

[jbellis]

No description provided.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
66.7% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[cassci-bot]

❌ Build ds-cassandra-pr-gate/PR-1472 rejected by Butler

---

10 new test failure(s) in 1 builds
See build details here

---

Found 10 new test failures

Test	Explanation	Branch history	Upstream history
...adRepairGuarantees.test_atomic_writes[blocking]	regression	🔴	🔵🔵🔵🔵🔵🔵🔵
o.a.c.i.s.c.VectorSiftSmallTest.testCompaction	regression	🔴	🔵🔵🔵🔵🔵🔵🔵
...i.s.c.VectorSiftSmallTest.testMultiSegmentBuild	regression	🔴	🔵🔵🔵🔵🔵🔵🔵
o.a.c.i.s.c.VectorSiftSmallTest.testSiftSmall	regression	🔴	🔵🔵🔵🔵🔵🔵🔵
...ePKWithBruteForceAndOnDiskGraphBasedScoring[ca]	regression	🔴	🔵🔵🔵🔵🔵🔵🔵
...t,varint>>,wide=true,scenario=POST_BUILD_QUERY]	regression	🔴	🔵🔵🔵🔵🔵🔵🔵
...<map<int,int>>>,wide=true,scenario=MIXED_QUERY]	regression	🔴	🔵🔵🔵🔵🔵🔵🔵
...et>,wide=false,scenario=COMPACTED_QUERY]	regression	🔴	🔵🔵🔵🔵🔵🔵🔵
...n.ConnectionTest.testMessageDeliveryOnReconnect	regression	🔴	🔵🔵🔵🔵🔵🔵🔵
o.a.c.u.b.BinLogTest.testTruncationReleasesLogS...	regression	🔴	🔵🔵🔵🔵🔵🔵🔵

---

Found 2 known test failures