This avoids a failure in at least one case when running only a single
test method rather than all tests in the module.

The issue came up when testing the following on Windows 10 Pro 64-bit:
HighPageTest.test_highlight_target_text_mouse
(cherry picked from commit 2af9f5d3)
Co-authored-by: Tal Einat <taleinat+github@gmail.com>