feat(persistent_merkle_tree): add batchGetRoot for 2x faster tree hashing #1390

Job	Run time
build & test (ubuntu-24.04-arm)	3m 53s
bindings - test	3m 47s
spec tests - prepare	1m 4s
build & test (macos-latest)	4m 4s
build & test (ubuntu-latest)	3m 53s
spec tests - bls	2m 42s
spec tests - ssz generic	2m 45s
slow tests	4m 23s
spec tests - ssz static minimal	20m 37s
build fuzz harnesses	37s
spec tests - ssz static mainnet	2m 9s
spec tests - mainnet (random)	7m 38s
spec tests - minimal (operations)	2m 5s
spec tests - mainnet (epoch_processing)	7m 13s
spec tests - mainnet (operations)	13m 4s
spec tests - mainnet (transition)	5m 43s
spec tests - minimal (rewards)	1m 3s
spec tests - mainnet (finality)	2m 14s
spec tests - minimal (merkle_proof)	59s
spec tests - minimal (transition)	2m 48s
spec tests - minimal (random)	1m 53s
spec tests - mainnet (sanity)	7m 56s
spec tests - minimal (fork)	2m 46s
spec tests - minimal (finality)	2m 24s
spec tests - mainnet (rewards)	3m 45s
spec tests - minimal (sanity)	2m 47s
spec tests - mainnet (merkle_proof)	1m 30s
spec tests - mainnet (fork)	5m 29s
spec tests - minimal (epoch_processing)	2m 46s
	2h 3m 57s

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