basalt-26.3: [timeout] sql: TestDistributedMergeStoragePrefixPreservedAcrossPauseResume failed

sql.TestDistributedMergeStoragePrefixPreservedAcrossPauseResume [failed](https://mesolite.cluster.engflow.com/invocations/default/3972bad9-cd6a-4d0d-96fe-e830383525c5?testReportRun=1&testReportShard=14&testReportAttempt=1#targets-Ly9wa2cvc3FsOnNxbF90ZXN0) on basalt-26.3 @ [56cb5d5d608e6e57059d3a85dfd948cc917c4a17](https://github.com/cockroachdb/cockroach/commits/56cb5d5d608e6e57059d3a85dfd948cc917c4a17):

```
=== RUN TestDistributedMergeStoragePrefixPreservedAcrossPauseResume
test_log_scope.go:172: test logs captured to: outputs.zip/logTestDistributedMergeStoragePrefixPreservedAcrossPauseResume397858278
test_log_scope.go:82: use -show-logs to present logs inline
test_server_shim.go:168: automatically injected a shared process virtual cluster under test; see comment at top of test_server_shim.go for details.
test_server_shim.go:639: DRPC is enabled (via testserver factory defaults)
indexbackfiller_test.go:1087: storage prefixes before pause: [nodelocal://1/]
indexbackfiller_test.go:1090: condition failed to evaluate within 30s: from indexbackfiller_test.go:1094: expected succeeded, got running

goroutine dump: /mnt/engflow/worker/work/0/exec/bazel-out/k8-fastbuild/testlogs/pkg/sql/sql_test/shard_14_of_16_run_1_of_3/test.outputs/goroutine_dump_4294150604.txt
panic.go:694: -- test log scope end --
test logs left over in: outputs.zip/logTestDistributedMergeStoragePrefixPreservedAcrossPauseResume397858278
--- FAIL: TestDistributedMergeStoragePrefixPreservedAcrossPauseResume (47.64s)
```

Parameters:
- attempt=1
- race=true
- run=1
- shard=14
Help

See also: [How To Investigate a Go Test Failure \(internal\)](https://cockroachlabs.atlassian.net/l/c/HgfXfJgM)

[This test on roachdash](https://roachdash.crdb.dev/?filter=status:open%20t:.*TestDistributedMergeStoragePrefixPreservedAcrossPauseResume.*&sort=title+created&display=lastcommented+project) | [Improve this report!](https://github.com/cockroachdb/cockroach/tree/master/pkg/cmd/bazci/githubpost/issues)

Jira issue: CRDB-67655

Start with pkg/sql/indexbackfiller_test.go around lines 1087-1094 and inspect the captured test logs and goroutine dump linked in the report. Investigate why TestDistributedMergeStoragePrefixPreservedAcrossPauseResume remains running after pause/resume under race execution; done means the failure is addressed and the test passes.

Written by the indexing model from the issue text.