replay: don't process async events when warping the clock

replay: don't process async events when warping the clock

Virtual clock is warped from iothread and vcpu thread. When the hardware
events associated with warp checkpoint, then interrupt delivering may be
non-deterministic if checkpoint is processed in different threads in record
and replay.
This patch disables event processing for clock warp checkpoint and leaves
all hardware events to other checkpoints (e.g., virtual clock).

Signed-off-by: Pavel Dovgalyuk <[email protected]>
Message-Id: <20180227095316.1060.4134.stgit@pasha-VirtualBox>
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Pavel Dovgalyuk <[email protected]>