Re: Fix pgbench --progress report under (very) low rate

> v3 rebase (after pgbench moved to src/bin) and minor style tweaking.

v4 adds a fix to another progress timing issue:

Currently if pgbench/postgres get stuck somewhere, the report catches up 
by repeating progresses several time in a row, which looks like that:
  progress: 10.0 s ...  progress: 11.0 s ... stuck...  progress: 14.2 s catchup for 11.0 -> 14.2  progress: 14.2 s
stupiddata  progress: 14.2 s stupid data  progress: 15.0 s ...  progress: 16.0 s ...
 

The correction removes the "stupid data" lines which compute a reports on 
a very short time, including absurd tps figures.

Yet again, shame on me in the first place for this behavior.

-- 
Fabien.