tst_qt_testrunner: make it runnable on windows

By making sure it invokes other python executables using the same
python interpreter.

Also on the tests that write to an XML file, close the file handle that
mkstemp() generates, otherwise Windows refuse to open and write to the
filename.

Side change:

+ For some tests, include all the environment instead of selecting
  specific env vars, in order to reduce verbosity.

Pick-to: 6.11 6.10 6.8
Change-Id: If4ba68b5f9bf64824c888b99e9525d4bdcf42037
Reviewed-by: Mårten Nordheim <[email protected]>
Reviewed-by: Edward Welbourne <[email protected]>

0 files changed, 0 insertions, 0 deletions