intermediate workspace display overload when executing 'test'

[Daniel J Sebald]

When running a test script from inside the GUI the Workspace window 
displays and updates the variables of "test.m".  It's a quick flash of 
characters, but execution is slowed enough to watch the variable values 
changing.

There is a screen image here:

https://savannah.gnu.org/bugs/index.php?39646

taken while running this script

for i=1:100
  test fftfilt
end

Other functions don't seem to do this.  Does anyone have an idea what 
line of code within test.m might cause the GUI to be refreshed?

Dan