Fix test SchemaRegionBasicTest

[kabo87777]

Fix non-deterministic test: testGetMatchedDevices in SchemaRegionBasicTest

Description

This PR fixes a non-deterministic test in SchemaRegionBasicTest.testGetMatchedDevices that was failing intermittently due to non-deterministic iteration order in the underlying schema region implementation.

Way to Reproduce

The non-deterministic behavior can be reproduced using NonDex, a tool that detects non-deterministic test behavior:

mvn -pl iotdb-core/datanode edu.illinois:nondex-maven-plugin:2.1.7:nondex \
    -Dtest=org.apache.iotdb.db.metadata.schemaRegion.SchemaRegionBasicTest \
    -DnondexRuns=3

Before the fix:

• Test would fail with NonDex seed 974622
• Error message : java.lang.AssertionError: expected:<[ShowDevicesResult{name='root.laptop.d1, rawNodes = null, isAligned = false, templateId = -1}, ShowDevicesResult{name='root.laptop.d1.s2, rawNodes = null, isAligned = false, templateId = -1}]> but was:<[ShowDevicesResult{name='root.laptop.d1, rawNodes = null, isAligned = false, templateId = -1}, ShowDevicesResult{name='root.laptop.d2, rawNodes = null, isAligned = false, templateId = -1}]>

Root Cause

The test was using limit 2 in the getMatchedDevices call, which returned different sets of devices depending on the non-deterministic iteration order of ConcurrentHashMap used throughout the schema region implementation:

1. Non-deterministic data structure: The schema region uses ConcurrentHashMap for storing child nodes in the MTree implementation
2. Iteration order dependency: ConcurrentHashMap.values().iterator() does not guarantee consistent ordering
3. Limit causing different results: With limit 2, the test would get different subsets of the 3 matching devices (root.laptop.d1, root.laptop.d1.s2, root.laptop.d2) depending on iteration order
4. NonDex detection: NonDex shuffles collection iteration order, exposing this non-deterministic behavior

Fix

• Removed the limit parameter: Changed from limit 2 to limit 0 (no limit) to retrieve all matching devices
• Updated expected results: Include all 3 devices that match the filter "laptop.d":
  • root.laptop.d1
  • root.laptop.d1.s2
  • root.laptop.d2
• Maintained HashSet comparison: The test already uses HashSet comparison which is order-independent

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This PR has:

• [ ] been self-reviewed.
  • [ ] concurrent read
  • [ ] concurrent write
  • [ ] concurrent read and write
• [ ] added documentation for new or modified features or behaviors.
• [ ] added Javadocs for most classes and all non-trivial methods.
• [ ] added or updated version, license, or notice information
• [ ] added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• [ ] added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage.
• [ ] added integration tests.
• [ ] been tested in a test IoTDB cluster.

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Key changed/added classes (or packages if there are too many classes) in this PR