[fix](docker) skip same-file juicefs hive jar copy

[xylaaaaa]

Summary

• avoid copying the JuiceFS Hadoop jar when the discovered source jar is already the same file under Hive auxlib
• compare source and target realpaths before cp -f so the Hive pipeline does not fail with a same-file copy error

Test Plan

• bash -n docker/thirdparties/run-thirdparties-docker.sh
• run a targeted shell harness that sets source_jar == target_jar and verifies ensure_juicefs_hadoop_jar_for_hive exits successfully with JuiceFS Hadoop jar already present in hive auxlib: juicefs-hadoop-1.3.1.jar

[hello-stephen]

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[xylaaaaa]

run buildall

[Copilot]

Pull request overview

This PR updates the thirdparty Docker harness to avoid failing the Hive setup when the discovered JuiceFS Hadoop jar is already located in Hive’s auxlib directory (same-file copy case).

Changes:

• Compute the expected Hive auxlib target jar path and skip copying when source/target resolve to the same file.
• Preserve existing behavior otherwise by syncing the jar into Hive auxlib.

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[Copilot]

This introduces a new hard dependency on the external realpath command in the Hive path. On environments where realpath isn’t available, ensure_juicefs_hadoop_jar_for_hive will fail even though the copy could succeed. Since the goal is just “same file” detection, consider using Bash’s file test [[ "$source_jar" -ef "$target_jar" ]] (same inode) to avoid external commands and handle symlink/hardlink cases more robustly.