fix sum decimal array overflow behavior with scalars #6431

Performance Regression: -10.22%

⚡ 5 improved benchmarks
❌ 2 regressed benchmarks
✅ 1128 untouched benchmarks
⏩ 1268 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
❌	Simulation	`encode_varbin[(1000, 2)]`	203.4 µs	226.5 µs	-10.22%
❌	Simulation	`encode_varbin[(1000, 4)]`	205.3 µs	228.5 µs	-10.14%
⚡	Simulation	`take_map[(0.05, 0.1)]`	792 µs	603 µs	+31.34%
⚡	Simulation	`take_map[(0.1, 0.1)]`	1,118.8 µs	921.3 µs	+21.44%
⚡	Simulation	`take_map[(0.05, 1.0)]`	4.1 ms	3.1 ms	+33.35%
⚡	Simulation	`take_map[(0.1, 1.0)]`	4.7 ms	3.5 ms	+34.59%
⚡	Simulation	`take_map[(0.1, 0.5)]`	2.8 ms	2.1 ms	+34.07%

_{Comparing ct/fix-decimal-overflow-scalar (838d354) with develop (aa55054)²}

1268 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. ↩
No successful run was found on develop (92156f5) during the generation of this report, so aa55054 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩