[SPARK-51268][SQL] Make `TreeNode` lock-free

[zhengruifeng]

What changes were proposed in this pull request?

Make TreeNode lock-free, by replace lazy val with BestEffortLazyVal

Why are the changes needed?

In several deadlock issues, we observed that the lock of TreeNode._hashCode is the root cause.

Does this PR introduce any user-facing change?

no

How was this patch tested?

ci

Was this patch authored or co-authored using generative AI tooling?

no

[dongjoon-hyun]

cc @JoshRosen and @cloud-fan

[cloud-fan]

thanks, merging to master!

[dongjoon-hyun]

Thank you, @zhengruifeng , @cloud-fan and all.