[MERGE] [Bug 226769] Disable some strace tests

[Vincent Ladeuil]

>>>>> "robert" == Robert Collins <robertc at robertcollins.net> writes:

<snip/>

    robert> Lets merge a patch which collects statistics on leaked threads from
    robert> tests, and reports at the end:
    robert>  - the number of tests where the thread count changed
    robert>  - the name of the first such test

Ideally we need a setUp/tearDown on the whole test suite for that
(and even more ideally some addCleanUp facility too).

But I'd prefer not implementing that right now but instead go the
_make_test_root way and use atexit too.

Thoughts ?

         Vincent