CNDB-14481: Fix IllegalStateException in SegmentMetadataBuilder

[pkolaczk]

If an index analyzer produced no terms for a row, the index
build could not complete and broke sstable flushing.

This commit makes the SegmentBuilder ignore the whole row
if there are no terms. Additionally more assertions / preconditions
have been added to improve diagnostics.

Fixes:
Failed to complete an index build
java.lang.IllegalStateException: Term range not set
at org.apache.cassandra.index.sai.disk.v1.SegmentMetadataBuilder.build(SegmentMetadataBuilder.java:145)
at org.apache.cassandra.index.sai.disk.v1.SegmentBuilder.flush(SegmentBuilder.java:470)
at org.apache.cassandra.index.sai.disk.v1.SSTableIndexWriter.flushSegment(SSTableIndexWriter.java:286)
at org.apache.cassandra.index.sai.disk.v1.SSTableIndexWriter.complete(SSTableIndexWriter.java:151)

[github-actions]

Checklist before you submit for review

• Make sure there is a PR in the CNDB project updating the Converged Cassandra version
• Use NoSpamLogger for log lines that may appear frequently in the logs
• Verify test results on Butler
• Test coverage for new/modified code is > 80%
• Proper code formatting
• Proper title for each commit staring with the project-issue number, like CNDB-1234
• Each commit has a meaningful description
• Each commit is not very long and contains related changes
• Renames, moves and reformatting are in distinct commits
• All new files should contain the DataStax copyright header instead of the Apache License one

[sonarqubecloud]

Quality Gate failed

Failed conditions
76.5% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud

[cassci-bot]

❌ Build ds-cassandra-pr-gate/PR-1808 rejected by Butler

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1 new test failure(s) in 2 builds
See build details here

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Found 1 new test failures

Test	Explanation	Branch history	Upstream history
o.a.c.u.b.BinLogTest.testTruncationReleasesLogS...	regression	🔴🔵	🔵🔵🔵🔵🔵🔵🔵

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Found 2 known test failures

[pkolaczk]

The coverage reported by Sonar is low because I added some Preconditions / asserts which must never fire. There should be no way to make them throw.