[tests] replace fixed tokio::time::sleep workarounds with wait_for_table_ready helper.

[slfan1989]

Purpose

Linked issue: close #562

This PR replaces fixed tokio::time::sleep workarounds in Rust integration tests with polling-based readiness helpers. This makes the tests less brittle on slow CI and avoids unnecessary waiting when the table or partition bucket leaders are ready earlier.

Brief change log

• Added readiness helpers in Rust integration test utils:
  • wait_for_table_ready
  • wait_for_table_buckets_ready
  • wait_for_partitions_ready
  • wait_for_partition_ready
  • wait_for_partition_buckets_ready
• Replaced fixed sleeps after table creation with table readiness polling.
• Replaced fixed sleeps after partition creation with partition readiness polling.
• Updated the RecordBatchLogReader integration tests to use the new helpers, including the multi-bucket case.

Tests

Exists Test.

API and Format

No.

Documentation

No.

[charlesdong1991]

tiny comment

[fresh-borzoni]

@slfan1989 Ty for the PR, LGTM overall, minor comment

nit: these three wait_for_* loops (+ wait_for_cluster_ready_with_sasl) are the same poll-until-timeout skeleton copy-pasted, differing only in the probe. Could pull out a small poll_until(timeout, interval, || probe) helper - basically the Rust version of Java's CommonTestUtils.waitUtil/waitValue.
Not blocking, just a thought since we're here.

[slfan1989]

@slfan1989 Ty for the PR, LGTM overall, minor comment

nit: these three wait_for_* loops (+ wait_for_cluster_ready_with_sasl) are the same poll-until-timeout skeleton copy-pasted, differing only in the probe. Could pull out a small poll_until(timeout, interval, || probe) helper - basically the Rust version of Java's CommonTestUtils.waitUtil/waitValue. Not blocking, just a thought since we're here.

Thanks for the suggestion! Updated. I factored out the shared poll-until-timeout skeleton into a small poll_until helper and reused it in the table/partition readiness helpers as well as wait_for_cluster_ready_with_sasl.

[fresh-borzoni]

@slfan1989 Thank you for the contribution, LGTM 👍
@charlesdong1991 all good from your side?