Test 1:
I was able to run `arc unit --everything` without the error thrown from T15200
Test 2:
I also tried this and it still works:
```
php -a
require 'src/applications/metamta/exception/PhabricatorMetaMTAReceivedMailProcessingException.php';
$asd = new PhabricatorMetaMTAReceivedMailProcessingException("1", "TEST MESSAGE");
var_dump($asd->getMessage());
var_dump($asd);
```
You get:
```
string(12) "TEST MESSAGE"
object(PhabricatorMetaMTAReceivedMailProcessingException)#1 (8) {
["message":protected]=>
string(4) "AHAH"
["string":"Exception":private]=>
string(0) ""
["code":protected]=>
int(0)
["file":protected]=>
string(12) "/tmp/asd.php"
["line":protected]=>
int(21)
["trace":"Exception":private]=>
array(0) {
}
["previous":"Exception":private]=>
NULL
["statusCode":"PhabricatorMetaMTAReceivedMailProcessingException":private]=>
string(3) "ASD"
}
```