[Patch #1520905] Attempt to suppress core file created by test_subprocess.py.

[Patch #1520905] Attempt to suppress core file created by test_subprocess.py.
Patch by Douglas Greiman.

The test_run_abort() testcase produces a core file on Unix systems,
even though the test is successful. This can be confusing or alarming
to someone who runs 'make test' and then finds that the Python
interpreter apparently crashed.