After this transport_test runs with all applicable sanitizers and only a few suppressions targeted at the one mode/sub-mode (exercise, SHM-classic) that needs them. Plus one little suppression for sub-mode SHM-jemalloc.

After this transport_test runs with all applicable sanitizers and only a few suppressions targeted at the one mode/sub-mode (exercise, SHM-classic) that needs them. Plus one little suppression for sub-mode SHM-jemalloc. #496