cli: make tests faster

[2501babe]

cli tests spin up a full test validator for every test case, which takes forever to run as we add more cases. it also runs cases in serial because running many test validators at once is cpu murder. we should be fine spinning up one single validator for all tests, and letting every case create its own rpc client and vote account

i noticed a few weeks ago std has LazyLock now, which is a threadsafe OnceCell, basically like lazy_static. could probably use that

(not a priority, do it if we add more program instructions)

[joncinque]

You can also consider what the token-cli tests do, using a custom test harness with libtest-mimic: https://github.com/solana-program/token-2022/blob/a26984d70b7a5d8e9f8a11615356772bb6454d9a/clients/cli/tests/command.rs#L78

[2501babe]

LazyLock is a no-go but i did try tokio OnceCell with TestValidator and it just doesnt work. running two test cases, whether you do #[serial] or not, use a shared RpcClient or create a new one every time, one test passes and the other hangs. probably some thread safety issue

i might try libtest-mimic next time... but tbh these just arent very important, its probably fine to just leave it and let ci take its time. actually i see the github workflows set up solana cli tools so if we have solana-test-validator in PATH maybe i can just use that