Synchronise lazy execstate before calling tasklet handlers.

Synchronise lazy execstate before calling tasklet handlers.

This ensures we are properly running on idle-vcpu state, which certain
things (e.g., use of vmx_vmcs_{enter,exit}) rely on. It also means we
don't need to do the same thing in the stopmachine_run handler.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>