test-aio-multithread: simplify test_multi_co_schedule

Instead of using qatomic_mb_{read,set} mindlessly, just use a per-coroutine
flag that requires no synchronization.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 file changed