SMC: Finer grained Mman / Invalidation Locks

[skmp]

Follow up from #1842,

We can use much finer grained mman / translation locks, vs the lock the world approach taken there.

• Use an inverval lock tree
• Lock based on arguments (eg, mmap w/o MAP_FIXED doesn't need to clear code caches, or mprotect that doesn't affect PROT_EXEC, etc)