The timeout for starting ModemManager on the test bus was 3s, which is
sufficient under normal conditions. However, when running ModemManager
tests on a build infrastructure under a heavy load, we've observed that
the timeout isn't always sufficient and that becomes the source of false
test failures. This patch increases the timeout to 30s, which shouldn't
introduce any unexpected behavior under normnal conditions while
addressing the timeout issue on heavily loaded systems.
This patch fixes the out-of-bounds array accesses in test-port-context.c,
which is detected by AddressSanitizer, by checking the index against the
array length before accessing the array.
