pg15b3: recovery fails with wal prefetch enabled

An internal VM crashed last night due to OOM.

When I tried to start postgres, it failed like:

< 2022-08-31 08:44:10.495 CDT  >LOG:  checkpoint starting: end-of-recovery immediate wait
< 2022-08-31 08:44:10.609 CDT  >LOG:  request to flush past end of generated WAL; request 1201/1CAF84F0, current
position1201/1CADB730
 
< 2022-08-31 08:44:10.609 CDT  >CONTEXT:  writing block 0 of relation base/16881/2840_vm
< 2022-08-31 08:44:10.609 CDT  >ERROR:  xlog flush request 1201/1CAF84F0 is not satisfied --- flushed only to
1201/1CADB730
< 2022-08-31 08:44:10.609 CDT  >CONTEXT:  writing block 0 of relation base/16881/2840_vm
< 2022-08-31 08:44:10.609 CDT  >FATAL:  checkpoint request failed

I was able to start it with -c recovery_prefetch=no, so it seems like
prefetch tried to do too much.  The VM runs centos7 under qemu.
I'm making a copy of the data dir in cases it's needed.

-- 
Justin