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/hello.py

@@ -1 +1,9 @@
-print("hello world")
+import hashlib
+
+
+
+# import sys
+# import urllib.request
+# with urllib.request.urlopen("http://justine.lol") as resp:
+#   sys.stdout.buffer.write(resp.read())
+# print("hello world")