tests: remove check2 timeouts in favor of meson

Meson already handles timeouts, configurable on the command line with
--timeout-multiplier.  They are set to 300s for all tests.

Part-of: <https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/807>

src/tests/volume-test.c

@@ -161,7 +161,6 @@ int main(int argc, char *argv[]) {
     s = suite_create("Volume");
     tc = tcase_create("volume");
     tcase_add_test(tc, volume_test);
-    tcase_set_timeout(tc, 120);
     suite_add_tcase(s, tc);
 
     sr = srunner_create(s);