tests,cputest: add volatile to prevent optimization

Upd ref score for three benchmarks

amtest: add `H` for displaying help msg

Amtest msg

Nemu

* update CTE API
* add dummy MPE API

am.include,nemu: refactor mmio address

am,arch: modify syscall registers as glibc

x86.h: fix a wrong decl of uint32_t

Code cleanups

Merge small testing project into amtest

Fix mainargs

* f-style format only avaliable with python version above 3.6

* add mainargs for x86-qemu, works good for litenes
* port microbench to mainargs
* fix native am
* fix litenes: not include generated .c
* restore back to main
* fix microbench at native
* start amtest, with interesting bug
* add unit test framework
* fix native archive removal

refactor: move compiler-rt into klib