The test_basic_multiple_interpreters_deleted_no_reset() test of test_import (previously in test_imp) leaks references but only when test_import is run with -jN option:

The test leaks since it was added by the commit bb0cf8f at Feb 27.

Leak with -j1 option:

$ ./python -m test -j1 -R 3:3 test_import -m test_basic_multiple_interpreters_deleted_no_reset 
test_import leaked [10, 10, 10] references, sum=30

No leak without the -j1 option, magic!

$ ./python -m test -R 3:3 test_import -m test_basic_multiple_interpreters_deleted_no_reset 
(...)
Tests result: SUCCESS

cc @ericsnowcurrently