Unicast recovery algorithm should account for all versions starting from "max(KCV)" onwards

[sbodagala]

The unicast recovery algorithm should ensure that all versions starting from "max(KCV)" onwards are included in the "unknownCommittedVersions" list. The current implementation allows the version whose prevVersion is equal to "max(KCV)" to be skipped (

foundationdb/fdbserver/TagPartitionedLogSystem.actor.cpp

Line 2333 in bfe0b4e

if (!(prevVersion == maxKCV || prevVersion == prevVersionMap[version])) {

) (and potentially a bunch of versions right after "max(KCV)") and could cause the algorithm to pick an incorrect recovery version. This PR corrects that check.

NOTE: A good unit test for this function "getRecoverVersionUnicast()" could have found this issue. But it could be tedious to write such a test because it requires the population of data structures like LogSets - we should think more about this.

Testing:
Found by a simulation test (multiple simulation tests found this issue, I think. Didn't look in-depth into all of them). Verified that they all succeed over this change. Also, multiple Joshua jobs run over this change (with version vector enabled) didn't show any similar failures.

Joshua job (with version vector disabled):

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[foundationdb-ci]

Result of foundationdb-pr-clang-ide on Linux RHEL 9

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[foundationdb-ci]

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[foundationdb-ci]

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[foundationdb-ci]

Result of foundationdb-pr-clang on Linux RHEL 9

• Commit ID: 05cbb0b
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[foundationdb-ci]

Result of foundationdb-pr on Linux RHEL 9

• Commit ID: 05cbb0b
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[foundationdb-ci]

Result of foundationdb-pr-macos on macOS Ventura 13.x

• Commit ID: 05cbb0b
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[foundationdb-ci]

Result of foundationdb-pr-cluster-tests on Linux RHEL 9

• Commit ID: 05cbb0b
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[dlambrig]

Created radar rdar://162067957 (create unit test for getRecoverVersionUnicast())