Bypass the first log quantum of each vcpu

Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>
Add conflict detection function to tm_unsync_commit

Now UNSYNC_PREEMPTION with HARD_MMU can support conflict detection and some basic
data analyse (e.g. conflict ratio).

Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>
Add __mmu_walk_spt_fast and optimize code routine

Add __mmu_walk_spt_fast (though not faster) and optimize code routine of mmu_walk_spt.

Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>