This autotest is unstable and sometimes hangs on Windows.
According to Qt Project CI logs, out of 301 builds of qtbase master (builds 02238 .. 02538), the test hung and was killed 8 times (i.e. it hung about 2.6% of the time).
Here's a sample log containing a failure: http://testresults.qt-project.org/ci/QtBase_master_Integration/build_02538/win32-msvc2010_Windows_7/log.txt.gz
When the test passes, its runtime is generally less than 1 second, so this is almost certainly a hang in the test (rather than the test being legitimately slow).
The source for the above metric is: