These two tests are working with refcounting

They were both failing on master:
- test_dumbdbm was failing in a test case that writes out some data to a database,
  closes it, then reopens the db and expects to be able to read the data.
- test_memoryview expected some weakrefs to get cleared at the right time.

test_socket.py appears to "pass" -- it exits with code 0, but it spams a bunch of
error messages from other threads.

from_cpython/Lib/test/test_dumbdbm.py

-# expected: fail
 """Test script for the dumbdbm module
    Original by Roger E. Masse
 """

from_cpython/Lib/test/test_memoryview.py

-# expected: fail
 """Unit tests for the memoryview
 
 XXX We need more tests! Some tests are in test_bytes