Add edge case handling for `batch_add` #523

Job	Run time
Rustfmt	16s
Bench (default)	4m 39s
Clippy lint checks	40s
Bench (asm)	6m 14s
Wasm-compatibility (wasm32-unknown-unknown)	2m 29s
Bench (bn256-table)	6m 38s
Test (default)	6m 22s
Wasm-compatibility (wasm32-wasi)	2m 30s
Spell Check with Typos	4s
Test (bn256-table)	6m 22s
Test (derive_serde)	6m 35s
Test (asm)	5m 54s
	48m 43s

Provide feedback