Remove legacy bootstrap #2398

Job	Run time
Linux [UBSAN] [lmdb \| clang]	40m 42s
macOS [UBSAN] [lmdb \| clang]	32m 40s
Linux [ASAN] [lmdb \| clang]	39m 50s
macOS [ASAN] [lmdb \| clang]	28m 18s
Linux [ASAN_INT] [lmdb \| clang] (Errors Ignored)	41m 48s
macOS [TSAN] [lmdb \| clang]	31m 44s
Linux [TSAN] [lmdb \| clang]	41m 23s
macOS [UBSAN] [rocksdb \| clang]	37m 50s
Linux [LEAK] [lmdb \| clang]	40m 40s
macOS [ASAN] [rocksdb \| clang]	38m 4s
Linux [UBSAN] [rocksdb \| clang]	47m 49s
Linux [ASAN] [rocksdb \| clang]	54m 59s
macOS [TSAN] [rocksdb \| clang]	52m 37s
Linux [ASAN_INT] [rocksdb \| clang] (Errors Ignored)	54m 7s
Linux [LEAK] [rocksdb \| clang]	52m 52s
	10h 35m 23s

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