add metrics for tick producer and poh_recorder (#15931)

measure/src/measure.rs

@@ -20,6 +20,10 @@ impl Measure {
         self.duration = duration_as_ns(&self.start.elapsed());
     }
 
+    pub fn as_ns(&self) -> u64 {
+        self.duration
+    }
+
     pub fn as_us(&self) -> u64 {
         self.duration / 1000
     }