Thanks, that reduces the refleaks shown for "./python -m test -R3:3 test_importlib" from 102 to 50 for me.

However, I suspect there may still be a leak in the machinery, as I'm still seeing the total number of objects growing when importing the array module and then dropping the references to it:

$ ./python -X showrefcount
Python 3.5.0a4+ (default:e729b946cc03+, May 24 2015, 00:58:18) 
[GCC 5.1.1 20150422 (Red Hat 5.1.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
[54384 refs, 15894 blocks]
>>> import array; del array; del sys.modules['array']
[54654 refs, 15974 blocks]
>>> import array; del array; del sys.modules['array']
[54695 refs, 15986 blocks]
>>> import array; del array; del sys.modules['array']
[54736 refs, 15997 blocks]
>>> import array; del array; del sys.modules['array']
[54777 refs, 16008 blocks]
>>> import array; del array; del sys.modules['array']
[54818 refs, 16019 blocks]
>>> import array; del array; del sys.modules['array']
[54859 refs, 16030 blocks]