Fix handling of totals in ProgressReporter

Here are my changes per pull request #113 and issue #112.  Instead of repeatedly setting the total every time a test is run, we can set it once when we start the progress bar, presumably because the number of tests should not be changing during a test run.
perhaps it is better to set total before starting the progress?
Now this order also works but looks unnatural and at some point progress may want to use total in start.
What do you think?