In ef0e8669fb we
had been seeing some significantly lower minvalues in
the jitter.Result test, so I lowered the mid-value rather
than having a very high minpercent, but it appears that the
variability of this result is very high, so we are still getting
the occasional high value, so reset the midval and just
have a bigger ranges on both sides, to try and keep the test
stable.
Signed-off-by: stevenhorsman <steven@uk.ibm.com>