Found by ASan, several leaks like:
Direct leak of 48 byte(s) in 2 object(s) allocated from:
#0 0x7f35fdc9c518 in calloc (/lib/x86_64-linux-gnu/libasan.so.5+0xe9518)
#1 0x55a77d6a4c6a in zalloc ../../git/weston/include/libweston/zalloc.h:38
#2 0x55a77d6a748e in create_shm_buffer ../../git/weston/tests/weston-test-client-helper.c:459
#3 0x55a77d6a78cd in create_shm_buffer_a8r8g8b8 ../../git/weston/tests/weston-test-client-helper.c:499
#4 0x55a77d6a4145 in surface_commit_color ../../git/weston/tests/pointer-shot-test.c:89
#5 0x55a77d6a4542 in pointer_cursor_retains_committed_buffer_after_reenter ../../git/weston/tests/pointer-shot-test.c:135
#6 0x55a77d6a4207 in wrappointer_cursor_retains_committed_buffer_after_reenter ../../git/weston/tests/pointer-shot-test.c:98
#7 0x55a77d6b15c2 in run_test ../../git/weston/tests/weston-test-runner.c:162
#8 0x55a77d6b1c63 in run_case ../../git/weston/tests/weston-test-runner.c:277
#9 0x55a77d6b1a09 in for_each_test_case ../../git/weston/tests/weston-test-runner.c:235
#10 0x55a77d6b1eeb in testsuite_run ../../git/weston/tests/weston-test-runner.c:311
#11 0x7f35f9510b6b in client_thread_routine ../../git/weston/tests/weston-test.c:479
#12 0x7f35fd7a4fa2 in start_thread /build/glibc-vjB4T1/glibc-2.28/nptl/pthread_create.c:486
#13 0x7f35fd8c64ce in clone (/lib/x86_64-linux-gnu/libc.so.6+0xf94ce)
Now this test has no more leaks.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>