Merge stat lowering and row count rewriting into single pass over expressions

[robert3005]

Instead of traversing expressions multiple times we do the lowering and row
count substitution at the same time. We also attempt removing duplicate
conditions from and/or predicates on the way up from stat rewriting.

Duplicate reduction is naive and only handles pairs of duplicates and not cases
where duplicates are one chain removed.

[codspeed-hq]

Merging this PR will degrade performance by 15.88%

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

❌ 1 regressed benchmark
✅ 1999 untouched benchmarks
⏩ 89 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	cold_misaligned[(64, 256)]	4.4 ms	5.2 ms	-15.88%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing rk/lessrewrites (84fdfb7) with develop (b363fb7)}

Footnotes

1. 89 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[robert3005]

double get_item slows down small prunes... need to figure out another option