Add time since genesis to sysvar::clock (#7289)

* genesis timestamp

* remove clock::create_account()

* ..

* add configure-able creation time

* dividing by 1T, should be dividing by 1B

sdk/src/sysvar/clock.rs

@@ -2,40 +2,8 @@
 //!
 pub use crate::clock::Clock;
 
-use crate::{
-    account::Account,
-    clock::{Epoch, Segment, Slot},
-    sysvar::Sysvar,
-};
+use crate::sysvar::Sysvar;
 
 crate::declare_sysvar_id!("SysvarC1ock11111111111111111111111111111111", Clock);
 
 impl Sysvar for Clock {}
-
-pub fn create_account(
-    lamports: u64,
-    slot: Slot,
-    segment: Segment,
-    epoch: Epoch,
-    leader_schedule_epoch: Epoch,
-) -> Account {
-    Clock {
-        slot,
-        segment,
-        epoch,
-        leader_schedule_epoch,
-    }
-    .create_account(lamports)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_new() {
-        let account = create_account(1, 0, 0, 0, 0);
-        let clock = Clock::from_account(&account).unwrap();
-        assert_eq!(clock, Clock::default());
-    }
-}