anv_tests tries to create a large number of threads, all of which wait
to be able to execute simultaneously, then launch a reasonable-size
workload.
Under load, cloning each of the 16 threads takes 15ms serially, for a
delay of 240ms before the tests start running; running the test 64
times gives us 15.36s for a single testcase in isolation, assuming that
the bits which aren't forking are free.
To give it the best shot at completing in time, mark it as a
non-parallelisable test (since Meson will also try to parallelise it
out), and also halve the number of runs it attempts. And then give it a
longer timeout so it doesn't fail even in extremis.
Signed-off-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31059>
Daniel Stone
a78539e704