[ASAN] some tests always fail when using sanitizer builds

But the test failures don't indicate anything about our code:

python-tox-test:

This fails because the sanitiser preload gets applied to python and gcc which reports leaks. In this case we should probably not do the preload anyway or not run the test.

ruby-example-test:

This case fails due to the preload not being active - however if the preload is added to this test then it finds leaks in the ruby interpreter. Again probably we should not include this test when sanitizers are being tested.