Record/replay can stall when there are no virtual devices that generate
events - it just uses all the time for vCPU thread. Therefore main loop
has to wait too much for the vCPU thread, because they are synchronized
in rr mode.
This patch does not let creating too long vCPU executions without
interrupting to main loop. It checks realtime timers that always exits
to control user input.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Message-Id: <157675958855.14346.18049977447896411847.stgit@pasha-Precision-3630-Tower>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>