Begin incorporating Python unit tests into build

We now build a separate APE binary for each test so they can run in
parallel. We've got 148 tests running fast and stable so far.

third_party/python/Lib/warnings.py

@@ -493,13 +493,13 @@ except ImportError:
     filters = []
     defaultaction = "default"
     onceregistry = {}
-
     _filters_version = 1
-
     def _filters_mutated():
         global _filters_version
         _filters_version += 1
 
+if __name__ == 'PYOBJ.COM':
+    import _warnings
 
 # Module initialization
 _processoptions(sys.warnoptions)