ci: skip test-execute on GH Actions under ASan

It seems to suffer from the same issue as on Travis CI, where the test
randomly fails due to timeouts in its subtests.

See: https://github.com/systemd/systemd/issues/10696#issuecomment-758501797

src/test/test-execute.c

@@ -897,8 +897,8 @@ int main(int argc, char *argv[]) {
         test_setup_logging(LOG_DEBUG);
 
 #if HAS_FEATURE_ADDRESS_SANITIZER
-        if (strstr_ptr(ci_environment(), "travis")) {
-                log_notice("Running on TravisCI under ASan, skipping, see https://github.com/systemd/systemd/issues/10696");
+        if (strstr_ptr(ci_environment(), "travis") || strstr_ptr(ci_environment(), "github-actions")) {
+                log_notice("Running on Travis CI/GH Actions under ASan, skipping, see https://github.com/systemd/systemd/issues/10696");
                 return EXIT_TEST_SKIP;
         }
 #endif