Add primitive kmalloc module (not being used yet).

Only hart 0 update ticks, so tickslock isn't needed at present.

Fix potential bugs of fs (eput and '0xff').

Pass most usertests on QEMU.

Abandon defs.h and some files;

Console

Fix xargs bugs.

M runs S'codes to handle ext-intr;
rustsbi still panic in some peculiar cases.

Delete some unused files.