Remove dead functions from BankStart and PohRecorder

Dead functions and doesn't seem useful to keep around.

poh/src/poh_recorder.rs

@@ -69,14 +69,6 @@ pub struct BankStart {
 }
 
 impl BankStart {
-    fn get_working_bank_if_not_expired(&self) -> Option<&Bank> {
-        if self.should_working_bank_still_be_processing_txs() {
-            Some(&self.working_bank)
-        } else {
-            None
-        }
-    }
-
     pub fn should_working_bank_still_be_processing_txs(&self) -> bool {
         Bank::should_bank_still_be_processing_txs(
             &self.bank_creation_time,
@@ -1119,16 +1111,6 @@ impl PohRecorder {
         }
     }
 
-    // Filters the return result of PohRecorder::bank_start(), returns the bank
-    // if it's still processing transactions
-    pub fn get_working_bank_if_not_expired<'a>(
-        bank_start: &Option<&'a BankStart>,
-    ) -> Option<&'a Bank> {
-        bank_start
-            .as_ref()
-            .and_then(|bank_start| bank_start.get_working_bank_if_not_expired())
-    }
-
     // Used in tests
     #[cfg(feature = "dev-context-only-utils")]
     pub fn schedule_dummy_max_height_reached_failure(&mut self) {