Fix flaky pipe auto split IT

[Caideyipi]

Motivation

IoTDBPipeAutoSplitIT assumes that auto split always leaves both history and realtime pipes visible immediately after creation. In practice, the history snapshot pipe can finish and be auto-dropped very quickly when there is no historical data, so SHOW PIPE may only return the realtime pipe and the test fails with expected 2 but was 1.

Modifications

• Relax the auto split assertion to require the realtime pipe and reject the original unsplit pipe.
• Allow the history pipe to be absent after automatic completion/drop.
• Keep validating the history pipe's sink option when that history pipe is still visible.

Tests

• Passed: git diff --check -- integration-test/src/test/java/org/apache/iotdb/pipe/it/dual/treemodel/auto/basic/IoTDBPipeAutoSplitIT.java
• Not run successfully locally: IoTDBPipeAutoSplitIT#testSingleEnv. Maven/JVM failed during compilation on this machine due Windows page file/native memory exhaustion.

[luoluoyuyu]

Review 总结

IT 修复思路正确：history pipe 在 snapshot 传完后可能被 auto-drop，原先用固定 size==2 + 顺序断言过于脆弱。assertAutoSplitResult 改为只要求存在 _realtime、不存在未拆分原名、且列表中仅有 _history/_realtime 子 pipe，更贴近真实行为。

建议合入（见行内 1 条 nit）。

[luoluoyuyu]

nit: Assert.assertFalse(showPipeResult.stream().anyMatch(...)) 可简写为 Assert.assertTrue(showPipeResult.stream().noneMatch(i -> Objects.equals(i.id, pipeName)))，语义相同。

另：若未来存在第三个与 pipeName 前缀相关但非 _history/_realtime 的 pipe（例如手动创建的 a2b_custom），allMatch 仍会通过。若需更严，可改为：

final long related = showPipeResult.stream().filter(i -> i.getId().startsWith(pipeName)).count();
Assert.assertEquals(2, related); // or 1 if history already dropped

当前实现已足够修 flake，非阻塞。