[1.0 -> main] Verify chain_head.dat does not exist on snapshot load

[heifner]

Spring verifies that shared_memory.bin does not exist when loading a snapshot. Also verify chain_head.dat does not exist when loading a snapshot.

warn  2024-08-19T11:32:37.908 nodeos    chain_plugin.cpp:1111         plugin_initialize    ] 3110006 plugin_config_exception: Incorrect plugin configuration
Snapshot can only be used to initialize an empty database, remove directory: /home/heifner/ext/leap/cmake-build-debug/bin/spring-testnet4-data/state
    {"d":"/home/heifner/ext/leap/cmake-build-debug/bin/spring-testnet4-data/state"}
    nodeos  chain_plugin.cpp:797 plugin_initialize

appbase: exception thrown during plugin "eosio::chain_plugin" initialization.
Incorrect plugin configuration
info  2024-08-19T11:32:37.909 nodeos    main.cpp:165                  operator()           ] nodeos version v1.0.0-rc1 v1.0.0-rc1-4c48ac7de86201d4b25a1e0e2d24cdb4c741efbb-dirty
info  2024-08-19T11:32:37.909 nodeos    main.cpp:69                   log_non_default_opti ] Non-default options: data-dir = spring-testnet4-data, config-dir = spring-testnet4, snapshot = snapshot-spring-8543320-2024-26-07_06-00.bin, chain-state-db-size-mb = 32000, http-server-address = 127.0.0.1:8899, p2p-listen-endpoint = 0.0.0.0:9899:0, signature-provider = EOS7GQpG7KWgw7FaFDnkua1LadP71nF1kVqAXZ5uD8apE3gUoCxX4=KEY:***, signature-provider = PUB_BLS_MEiD85FQ_7-WMBno5xit7-kHcCaJak7UVtcFQayDfneJCQT1mleNd-FQ9kBRHL4A_kHg41rEjhHXlfiH0GWqB2PP6mRUBR_wiFwOsO8lKUtDa_mBjtGSUVIo2sQWKDMGjEGASA=KEY:***, producer-name = zombiezombie, p2p-peer-address = p2p.spring-beta4.jungletestnet.io:9898, p2p-peer-address = 3.227.1.63:1444, p2p-peer-address = savanna.genereos.io:9876, p2p-peer-address = jungleb4.maroonspoon.com:9876, p2p-peer-address = p2p.spring-beta.jungletestnet.io:9898
error 2024-08-19T11:32:37.909 nodeos    main.cpp:224                  main                 ] 3110006 plugin_config_exception: Incorrect plugin configuration
Snapshot can only be used to initialize an empty database, remove directory: /home/heifner/ext/leap/cmake-build-debug/bin/spring-testnet4-data/state
    {"d":"/home/heifner/ext/leap/cmake-build-debug/bin/spring-testnet4-data/state"}
    nodeos  chain_plugin.cpp:797 plugin_initialize
rethrow
    {}
    nodeos  chain_plugin.cpp:1111 plugin_initialize

Merges release/1.0 into main including #581

Resolves #559

[ericpassmore]

Note:start
group: STABILITY
category: INTERNALS
summary: Validate chain_head is not present when loading a snapshot.
Note:end