The iperf version used in older version of CI docker images had the
following output format:
[ 3] 0.0-10.0 sec 1.25 MBytes 1.05 Mbits/sec 0.000 ms 0/ 892 (0%)
The newer iperf version which was recently included in the container
prints more digits after the decimal point:
[ 3] 0.0000-10.0148 sec 1.25 MBytes 1.05 Mbits/sec 0.002 ms 0/ 895 (0%)
The regular expression to match this line expected a single zero after
the decimal point, so the new format no longer matches.
The fix is to expect any number of digits in the fractional part.
d2e519012c