Clones the EVM and tx environments, runs a fork operation that may modify them, then writes
them back. This is the common pattern for all fork-switching cheatcodes (rollFork, selectFork,
createSelectFork).
Invalidates the fork DB cache after a vm.rpc call on the active fork that mutates the node
directly (bypassing the cache), so later DB reads (e.g. the broadcast simulation runner)
re-fetch the new value. Only well-known Anvil/Hardhat account/storage setters are handled;
chain-advancing methods (e.g. eth_sendTransaction) need re-forking, not eviction.