TEST_ASSERT jumps to the exit label, so it must not be called from
cleanup code executed after the exit label. It's legitimate (and
indeed very common) to call PSA_DONE in cleanup code, so PSA_DONE must
not jump to exit.
Define an auxiliary function test_fail_if_psa_leaking() that calls
test_fail() with the error message provided by
mbedtls_test_helper_is_psa_leaking(). This function currently needs to
be in helpers.function rather than in a PSA-specific helper file
because it calls test_fail which is defined in helpers.function.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>