upload anaconda core dump if it appears

Summary:
When anaconda manages to actually crash the python interpreter,
there should be a /tmp/anaconda.core containing the core dump
(per clumens, see calls to 'gcore' in isys.c). Let's upload it.
This might help us track down the mysterious occasional crashes
openQA seems to trigger (RHBZ #1289704)

Test Plan:
Try and trigger a python crash and see if the
file got uploaded. Of course, I did an entire freaking run on
staging and for *ONCE* not one test hit the mysterious crash,
thanks Murphy. I did at least check that this doesn't break
a 'normal' failure, if the file isn't there things don't
explode.

Reviewers: jskladan, garretraziel

Reviewed By: garretraziel

Subscribers: tflink

Differential Revision: https://phab.qadevel.cloud.fedoraproject.org/D686

lib/anacondatest.pm

@@ -42,6 +42,9 @@ sub post_fail_hook {
         # Upload /var/log
         script_run "tar czf /tmp/var_log.tar.gz /var/log";
         upload_logs "/tmp/var_log.tar.gz";
+
+        # Upload anaconda core dump, if there is one
+        upload_logs "/tmp/anaconda.core";
     }
     else {
         save_screenshot;