fdtrack: emit the most common stack in the abort message.

}

static void android_server_SystemServer_fdtrackAbort(JNIEnv*, jobject) {

    raise(BIONIC_SIGNAL_FDTRACK);

    // Wait for a bit to allow fdtrack to dump backtraces to logcat.

    std::this_thread::sleep_for(5s);

    // Abort on a different thread to avoid ART dumping runtime stacks.

    std::thread([]() {

        LOG_ALWAYS_FATAL("b/140703823: aborting due to fd leak: check logs for fd "

                         "backtraces");

    }).join();

    sigval val;

    val.sival_int = 1;

    sigqueue(getpid(), BIONIC_SIGNAL_FDTRACK, val);

}

static jlong android_server_SystemServer_startIncrementalService(JNIEnv* env, jclass klass,