util: optimize hexToBytes #9744

Job	Run time
vm-api	3m 19s
vm-benchmarks	2m 35s
vm-blockchain (--fork=Berlin --dir=GeneralStateTests/stTimeConsuming)	4m 13s
vm-blockchain (--fork=Berlin --excludeDir=stTimeConsuming)	8m 16s
vm-state (London)	8m 10s
vm-blockchain (--fork=London --dir=GeneralStateTests/stTimeConsuming)	4m 4s
vm-state (Berlin)	7m 56s
vm-state (Paris)	8m 23s
vm-blockchain (--fork=London --excludeDir=stTimeConsuming)	9m 41s
vm-state (MuirGlacier)	7m 29s
vm-blockchain (--fork=Istanbul --dir=GeneralStateTests/stTimeConsuming --expected-test-amount=15561)	4m 21s
vm-state (Istanbul)	7m 19s
vm-blockchain (--fork=Istanbul --excludeDir=stTimeConsuming --expected-test-amount=19817)	7m 43s
vm-state (Shanghai)	8m 23s
vm-blockchain (--fork=Paris --dir=GeneralStateTests/stTimeConsuming)	4m 9s
vm-blockchain-extended	0s
vm-state-extended	0s
vm-blockchain (--fork=Paris --excludeDir=stTimeConsuming)	9m 4s
vm-state (Cancun)	8m 20s
vm-blockchain (--fork=ArrowGlacierToMergeAtDiffC0000)	2m 45s
vm-blockchain (--fork=Shanghai --dir=GeneralStateTests/stTimeConsuming)	3m 59s
vm-blockchain (--fork=Shanghai --excludeDir=stTimeConsuming)	9m 29s
vm-blockchain (--fork=Cancun --dir=GeneralStateTests/stTimeConsuming)	4m 12s
vm-blockchain (--fork=Cancun --excludeDir=stTimeConsuming)	9m 31s
	2h 23m 21s

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