testenv: testsuite: use rsync with --archive

When running in podman, the source files from the testsuite get copied
to a temporary directory to build the testsuites out-of-tree (avoiding
conflicts with possibly incompatible binary objects that may exist from
previously building the testsuites on the host).

This also copies additional scripts for preparation / clean up that may
be used in testenv.cfg. Use the --archive flag with rsync to ensure
that the executability is the same. I could have also used
--executability, but --archive contains two other existing flags and
more flags which may help us from running into unexpected situations
such as this one.

Without this patch, there was a bug when:
* first creating a shell script but not making it executable
* running testenv with podman (where rsync runs and creates the file
  initially without executable permissions)
* making the script executable
* running testenv with podman again, rsync will not adjust the
  permissions for the copy of the file
* user wonders why there is a "sh: 1: script.sh: Permission denied"
  error

Change-Id: Ia9737bd8ba22a555615862bf5e14dbdf0dea19b4
---
M _testenv/testenv/testsuite.py
1 file changed, 1 insertion(+), 2 deletions(-)