Remove these old warning annotations

test/tests/gzip_test.py

-# allow-warning: import level 0 will be treated as -1
 import gzip
 import io
 

test/tests/io_test.py

-# allow-warning: import level 0 will be treated as -1
 import io
 filename = "io_test_.txt"
 

test/tests/optparse_test.py

-# allow-warning: import level 0 will be treated as -1
 # Simple optparse test, taken from the optparse.py docstring:
 
 from optparse import OptionParser

test/tests/pickle_test.py

-# allow-warning: import level 0 will be treated as -1
-
 import pickle
 
 l = [[], (123,)]

test/tests/prevent_nonascii_attrs.py

-# allow-warning: import level 0 will be treated as -1
 # skip-if: '-x' in EXTRA_JIT_ARGS
 
 def f(a):

test/tests/str_encode_decode.py

-# allow-warning: import level 0 will be treated as -1!
 def test(string, encoding):
  s = string.encode(encoding)
  print encoding, s

test/tests/unicode_test.py

 # skip-if: '-x' in EXTRA_JIT_ARGS
-# allow-warning: import level 0 will be treated as -1
 
 print repr(unicode())
 print repr(unicode('hello world'))