add native stake program

[2501babe]

this makes it easy to write tests that use test_case to run against both native and bpf stake to confirm the results are the same

i wasnt entirely use on naming stake_program vs solana_stake_program, i think the latter is what we prefer now, and we might want to rename system_program to solana_system_program

[buffalojoec]

Do you mind putting this behind a feature flag? How about we just use all-builtins, and I can stick other builtins in here too later, like vote.

[2501babe]

i didnt add system_program to the feature since the bpf test program depends on it, i think this is fine until we are working on a bpf system program

[buffalojoec]

Yep, works for me, thanks!