tests/basics requires python3.3

tests/bytecode/run-tests already uses puthon3.3, so let's just use it here
too.

Fore reference, errors with python 3.2.3:

  File "tests/generator1.py", line 12
    return None
SyntaxError: 'return' with argument inside generator

  File "tests/list_clear.py", line 3, in <module>
    x.clear()
AttributeError: 'list' object has no attribute 'clear'

etc.

tests/basics/run-tests

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 
 RM="/bin/rm -f"
-CPYTHON3=python3
+CPYTHON3=python3.3
 MP_PY=../../unix/py
 
 numtests=0