timer: introduce new QEMU_CLOCK_VIRTUAL_RT clock This patch introduces new QEMU_CLOCK_VIRTUAL_RT clock, which should be used for icount warping. In the next patch, it will be used to avoid a huge icount warp when a virtual machine is stopped for a long time. Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>