Use `asio` namespace alias #1113

Job	Run time
Linux [UBSAN] [lmdb \| clang]	38m 15s
Linux [ASAN] [lmdb \| clang]	40m 10s
macOS [UBSAN] [lmdb \| clang]	29m 23s
Linux [ASAN_INT] [lmdb \| clang] (Errors Ignored)	38m 10s
macOS [ASAN] [lmdb \| clang]	26m 1s
Linux [TSAN] [lmdb \| clang] (Errors Ignored)	40m 31s
Linux [LEAK] [lmdb \| clang] (Errors Ignored)	37m 45s
macOS [TSAN] [lmdb \| clang] (Errors Ignored)	27m 34s
Linux [UBSAN] [rocksdb \| clang]	44m 4s
Linux [ASAN] [rocksdb \| clang]	48m 35s
macOS [UBSAN] [rocksdb \| clang]	37m 44s
Linux [ASAN_INT] [rocksdb \| clang] (Errors Ignored)	48m 18s
macOS [ASAN] [rocksdb \| clang]	35m 34s
Linux [TSAN] [rocksdb \| clang] (Errors Ignored)	1h 35m 53s
macOS [TSAN] [rocksdb \| clang] (Errors Ignored)	47m 26s
Linux [LEAK] [rocksdb \| clang] (Errors Ignored)	47m 31s
	11h 22m 54s

Provide feedback