Wrap read() with the CHECK() used elsewhre in the test program, in order
to render out the compiler warning represented by this transcript:
➜ pipewire (af38edea) ✔ make
ninja -C /home/jarkko/Projects/pipewire/build
ninja: Entering directory `/home/jarkko/Projects/pipewire/build'
[6/397] Compiling C object spa/plugins/alsa/test-timer.p/test-timer.c.o
../spa/plugins/alsa/test-timer.c: In function ‘main’:
../spa/plugins/alsa/test-timer.c:195:3: warning: ignoring return value of ‘read’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
195 | read(state.timerfd, &expirations, sizeof(expirations));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@iki.fi>
