asan reported leak in the css tests
Leaks like this are reported by many of the css tests when running the testsuite under asan:
=================================================================
==118142==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 24 byte(s) in 1 object(s) allocated from:
#0 0x7f796c2f8a20 in __interceptor_realloc (/lib64/libasan.so.6+0xb0a20)
#1 0x7f796ad55ad9 in g_realloc ../glib/gmem.c:171
#2 0x7f796b76b2be in gtk_css_selector_new ../gtk/gtkcssselector.c:919
#3 0x7f796b76fd96 in gtk_css_selector_parse_simple_selector ../gtk/gtkcssselector.c:1500
#4 0x7f796b76fd96 in _gtk_css_selector_parse ../gtk/gtkcssselector.c:1555
#5 0x7f796b2da565 in parse_selector_list ../gtk/gtkcssprovider.c:768
#6 0x7f796b2da565 in parse_ruleset ../gtk/gtkcssprovider.c:906
#7 0x7f796b2db6f7 in parse_statement ../gtk/gtkcssprovider.c:941
#8 0x7f796b2db6f7 in parse_stylesheet ../gtk/gtkcssprovider.c:956
#9 0x7f796b2db6f7 in gtk_css_provider_load_internal ../gtk/gtkcssprovider.c:1062
#10 0x7f796b2dd1ee in gtk_css_provider_load_from_file ../gtk/gtkcssprovider.c:1132
#11 0x7f796b2dd2cf in gtk_css_provider_load_from_path ../gtk/gtkcssprovider.c:1156
#12 0x402d64 in parse_css_file ../testsuite/css/parser/test-css-parser.c:181
#13 0x7f796ad7c191 in test_case_run ../glib/gtestutils.c:2649
#14 0x7f796ad7c54d in g_test_run_suite_internal ../glib/gtestutils.c:2737
#15 0x7f796ad7c5f6 in g_test_run_suite_internal ../glib/gtestutils.c:2749
#16 0x7f796ad7c5f6 in g_test_run_suite_internal ../glib/gtestutils.c:2749
#17 0x7f796ad7c5f6 in g_test_run_suite_internal ../glib/gtestutils.c:2749
#18 0x7f796ad7c5f6 in g_test_run_suite_internal ../glib/gtestutils.c:2749
#19 0x7f796ad7c5f6 in g_test_run_suite_internal ../glib/gtestutils.c:2749
#20 0x7f796ad7c5f6 in g_test_run_suite_internal ../glib/gtestutils.c:2749
#21 0x7f796ad7c5f6 in g_test_run_suite_internal ../glib/gtestutils.c:2749
#22 0x7f796ad7c5f6 in g_test_run_suite_internal ../glib/gtestutils.c:2749
#23 0x7f796ad7c80d in g_test_run_suite ../glib/gtestutils.c:2824
#24 0x7f796ad7b3e9 in g_test_run ../glib/gtestutils.c:2061
#25 0x4025fe in main ../testsuite/css/parser/test-css-parser.c:356
#26 0x7f796a8cf041 in __libc_start_main (/lib64/libc.so.6+0x27041)
SUMMARY: AddressSanitizer: 24 byte(s) leaked in 1 allocation(s).