Get Python tests working under ASan/CI

[jsiwek]

i.e. address this:

broker/ci/test.sh

Lines 10 to 15 in 8899280

	# Python tests under ASan are problematic for various reasons, so skip
	# e.g. need LD_PRELOAD, some specific compiler packagings are
	# buggy when preloaded due to missing libasan compilation flag,
	# leaks are miss-reported so have to disable leak checking, and
	# finally most tests end up timing out when run under ASan anyway.
	CTEST_OUTPUT_ON_FAILURE=1 ctest -E python

Otherwise, can be a matter of luck whether problems like #153 (comment) get caught early.