Make test playback more reliable.

Since we changed now the axis ranges are set, this change to the test ensures
that we get a consistent axis range on different platforms with different
window sizes.

Change-Id: I50281966fb054aa1c8cb6f1afab606bb41f6d3f1
Merge topic '13818_fix_plot_min_max' into next

7c67595 Make test playback more reliable.