Bug 1239738 - Handle artifact builds with no test binaries cleanly. r=ahunt

DONTBUILD NPOTB on a CLOSED TREE

--HG--
extra : commitid : FGUTtsps8la
extra : amend_source : 0111b1b9551a9d93749dd81dc961d73d2965ee65

python/mozbuild/mozbuild/artifacts.py

@@ -123,9 +123,9 @@ class ArtifactJob(object):
         tests_artifact = None
         for artifact in artifacts:
             name = artifact['name']
-            if self._package_re.match(name):
+            if self._package_re and self._package_re.match(name):
                 yield name
-            elif self._tests_re.match(name):
+            elif self._tests_re and self._tests_re.match(name):
                 tests_artifact = name
                 yield name
             else: