system time may be incorrect

## Bug Report

### What did you do?
Run Jepsen test and configure with the list-append workload and the kill/pause/partition nemesis.

### What did you expect to see?
The system time should be correct

### What did you see instead?
We frequently observed the following error in the logs. We actually didn't change any clocks, so the system time should be correct and I think this error shouldn't appear here:
`./tikv list-append/20230329T041811.375Z/n4/pd.log:[2023/03/29 04:49:05.266 +00:00] [ERROR] [tso.go:210] ["system time may be incorrect"] [last=2023/03/29 04:49:05.423 +00:00] [next=2023/03/29 04:49:05.266 +00:00] [error="[PD:common:ErrIncorrectSystemTime]incorrect system time"]`

### What version of PD are you using (`pd-server -V`)?
v6.1.2