feat(fqdn): Limit the cache size on dns_resolve #2515

Job	Run time
Lint	13s
IWYU	49m 17s
Build Release	45m 29s
macOS	6h 0m 15s
Build ASAN	41m 15s
Build with jemalloc	45m 13s
Test ASAN	0s
Test with jemallc (dsn_utils_tests)	3m 54s
Test Release (backup_restore_test)	7m 19s
Test Release (base_api_test)	21m 56s
Test Release (base_test)	3m 2s
Test Release (bulk_load_test)	17m 37s
Test Release (dsn_aio_test)	3m 2s
Test Release (dsn_block_service_test)	3m 3s
Test Release (dsn_client_test)	3m 19s
Test Release (dsn.failure_detector.tests)	5m 30s
Test Release (dsn_http_test)	3m 18s
Test Release (dsn_meta_state_tests)	3m 8s
Test Release (dsn.meta.test)	27m 27s
Test Release (dsn_nfs_test)	3m 2s
Test Release (dsn_ranger_tests)	3m 33s
Test Release (dsn_replica_backup_test)	3m 19s
Test Release (dsn_replica_bulk_load_test)	3m 2s
Test Release (dsn_replica_dup_test)	3m 21s
Test Release (dsn_replica_split_test)	3m 4s
Test Release (dsn.replica.test)	3m 14s
Test Release (dsn_replication_common_test)	3m 2s
Test Release (dsn.replication.simple_kv)	3m 16s
Test Release (dsn.rep_tests.simple_kv)	5m 3s
Test Release (dsn_runtime_tests)	5m 2s
Test Release (dsn_security_tests)	3m 1s
Test Release (dsn_utils_tests)	3m 35s
Test Release (dsn.zookeeper.tests)	3m 7s
Test Release (pegasus_geo_test)	4m 19s
Test Release (pegasus_rproxy_test)	4m 53s
Test Release (pegasus_unit_test)	4m 8s
Test Release (recovery_test)	7m 43s
Test Release (restore_test)	5m 0s
Test Release (security_test)	3m 1s
Test Release (throttle_test)	21m 2s
	12h 23m 4s

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