Fix ledger_priority.sequential_blocks testcase (#4805) #2517

Job	Run time
Linux [UBSAN] [lmdb \| clang]	36m 44s
macOS [UBSAN] [lmdb \| clang]	35m 52s
Linux [ASAN] [lmdb \| clang]	36m 11s
macOS [ASAN] [lmdb \| clang]	28m 31s
Linux [ASAN_INT] [lmdb \| clang] (Errors Ignored)	37m 39s
macOS [TSAN] [lmdb \| clang]	29m 12s
Linux [TSAN] [lmdb \| clang]	49m 33s
macOS [UBSAN] [rocksdb \| clang]	36m 32s
Linux [LEAK] [lmdb \| clang]	37m 11s
macOS [ASAN] [rocksdb \| clang]	34m 39s
Linux [UBSAN] [rocksdb \| clang]	47m 26s
macOS [TSAN] [rocksdb \| clang]	47m 36s
Linux [ASAN] [rocksdb \| clang]	51m 38s
Linux [ASAN_INT] [rocksdb \| clang] (Errors Ignored)	54m 59s
Linux [LEAK] [rocksdb \| clang]	54m 9s
	10h 17m 52s

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