Fix dmake_test_get_results on non-empty target dir, i.e. on local machine (#484)
Fix dmake_test_get_results on non-empty target dir, i.e. on local machine (#484)

running locally tests 2 times results in unexpected result:
docker cp mycontainer:/app/cover/ cover/
cover/ is ok

second run:
docker cp mycontainer:/app/cover/ cover/
cover/cover/ is created, it should not exist

For files and not directory it already worked OK because nesting is
not possible.

solution: docker cp on parent path is idempotent.

On jenkins we always create a unique temporary directory, so there is
never a 'second run' on an existing target directory: that's why we
never saw any issue on test results collection on jenkins.
Deepomatic/dmake,Deepomatic/dmake,Deepomatic/dmake,Deepomatic/dmake