refactor: Parallel Tests

- `disabled_clamav_spamassassin`:
  - Just shuffling the test order around, and removing the restart test at the end which doesn't make sense.

- `postscreen`:
  - Now uses common helper for getting container IP
  - Does not appear to need the `NET_ADMIN` capability?
  - Reduced startup time for the 2nd container + additional context about it's relevance.
  - Test cases are largely the same, but refactored the `nc` alternative that properly waits it's turn. This only needs to run once. Added additional commentary and made into a generic method if needed in other tests.

- `fail2ban`:
  - Use the common container IP helper method.
  - Postscreen isn't affecting this test, it's not required to do the much slower exchange with the mail server when sending a login failure.
  - IP being passed into ENV is no longer necessary.
  - `sleep 5` in the related test cases doesn't seem necessary, can better rely on polling with timeout.
  - `sleep 10` for `setup.sh` also doesn't appear to be necessary.

- `postgrey`:
  - Reduced POSTGREY_DELAY to 3, which shaves a fair amount of wasted time while still verifying the delay works.
  - One of the checks in `main.cf` doesn't seem to need to know about the earlier spamhaus portion of the line to work, removed.
  - Better test case descriptions.
  - Improved log matching via standard method that better documents the expected triplet under test.
  - Removed a redundant whitelist file and test that didn't seem to have any relevance. Added a TODO with additional notes about a concern with these tests.
  - Reduced test time as 8 second timeouts from `-w 8` don't appear to be required, better to poll with grep instead.
  - Replaced `wc -l` commands with a new method to assert expected line count, better enabling assertions on the actual output.

- `undef_spam_subject`:
  - Split to two separate test cases, and initialize each container in their case instead of `setup_file()`, allowing for using the default `teardown()` method (and slight benefit if running in parallel).

- `permit_docker`:
  - Not a parallel test, but I realized that the repeat helper methods don't necessarily play well with `run` as the command (can cause false positive of what was successful).

test/tests/parallel/set1/spam_virus/disabled_clamav_spamassassin.bats

@@ -29,22 +29,17 @@ function teardown_file() { _default_teardown ; }
   assert_failure
 }
 
-@test "${TEST_NAME_PREFIX} SA - Amavis integration should not be active" {
-  _run_in_container /bin/sh -c "grep -i 'ANTI-SPAM-SA code' /var/log/mail/mail.log | grep 'NOT loaded'"
-  assert_success
-}
-
 @test "${TEST_NAME_PREFIX} ClamAV - Amavis integration should not be active" {
   _run_in_container grep -i 'Found secondary av scanner ClamAV-clamscan' /var/log/mail/mail.log
   assert_failure
 }
 
-@test "${TEST_NAME_PREFIX} SA should not be called" {
+@test "${TEST_NAME_PREFIX} SA - Amavis integration should not be active" {
+  _run_in_container bash -c "grep -i 'ANTI-SPAM-SA code' /var/log/mail/mail.log | grep 'NOT loaded'"
+  assert_success
+}
+
+@test "${TEST_NAME_PREFIX} SA - should not have been called" {
   _run_in_container grep -i 'connect to /var/run/clamav/clamd.ctl failed' /var/log/mail/mail.log
   assert_failure
 }
-
-@test "${TEST_NAME_PREFIX} ClamAV process should not be restarted when killed" {
-  _run_in_container /bin/bash -c "pkill -f clamd && sleep 10 && ps aux --forest | grep -v grep | grep '/usr/sbin/clamd'"
-  assert_failure
-}