program: test replenish for sub-minimum delegation

[2501babe]

while looking at onchain svsp transactions i noticed people will not uncommonly replenish in the thousands of lamports and realized we dont have tests that these instructions will still succeed after the minimum delegation goes to 1sol. the logic is clever... too clever to let it go untested:

let must_delegate_onramp = match option_onramp_status.unwrap_or_default() {
    // activating
    StakeActivationStatus {
        effective: 0,
        activating,
        deactivating: 0,
    } if activating > 0 => {
        onramp_non_rent_lamports >= minimum_delegation
            && onramp_non_rent_lamports > activating
    }   
    // inactive, or deactivating this epoch due to DeactivateDelinquent
    // effective may be nonzero here because we are using the status prior to MoveStake
    StakeActivationStatus {
        effective: _,
        activating: 0,
        deactivating,
    } if deactivating == 0 || onramp_deactivation_epoch == clock.epoch => {
        onramp_non_rent_lamports >= minimum_delegation
    }   
    // partially active, partially inactive, or some state beyond mortal reckoning
    _ => false,
};

also i cover the no-op cases that i previously skipped