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/Python/errors.c

@@ -1034,16 +1034,12 @@ done:
     PyErr_Clear(); /* Just in case */
 }
 
-extern PyObject *PyModule_GetWarningsModule(void);
-
-
 void
 PyErr_SyntaxLocation(const char *filename, int lineno)
 {
     PyErr_SyntaxLocationEx(filename, lineno, -1);
 }
 
-
 /* Set file and line information for the current exception.
    If the exception is not a SyntaxError, also sets additional attributes
    to make printing of exceptions believe it is a syntax error. */