ci: bump test timeouts

This is prompted by the spurious CI failure
https://gitlab.freedesktop.org/wayland/weston/-/jobs/13891809


saying:

31/36 output-damage                          TIMEOUT        122.52s   8 subtests passed
32/36 output-transforms                      TIMEOUT        122.52s   16 subtests passed
33/36 subsurface                             TIMEOUT        122.52s
34/36 xwayland                               TIMEOUT        122.51s
35/36 ivi-shell-app                          TIMEOUT        122.51s
ERROR: Job failed: execution took longer than 5m0s seconds

That is hitting both kinds of timeouts at the same time: the per-test
timeouts, and the CI job total timeout.

That run seems to have had a particularly ill fortune, as a simple retry
finished the same job in 2 minutes, and the longest running test took
only 24 seconds.

Nevertheless, by Daniel Stone's suggestion let's bump both timeouts:

- the per-test timeout to 120 seconds, which with the multiplier in CI
  goes up to 8 minutes

- the job timeout for all build related jobs to 15 minutes

The timeout for tests_standalone is not bumped as we are not adding
significant amounts of new tests there.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>