kern: devirtualize most things that are free to devirtualize (see #1672)

kern: optimize timespan -> tick codegen, improve .text layout

kern: use optimized red black tree finds for remaining holdouts

kern: devirtualize several KAutoObject functions

kern: KCacheHelper: better reflect nintendo coremask clearing logic

kern: devirtualize remaining vcall for class token/dyncast

kern: avoid constexpr init for many objects (avoids unnecessary memory clear) (#1668)

kern: use new AtomicRef, use Atomic<bool>

util: better match true std::atomic semantics

exo: use the fancy new optimal atomics

kern/util: use custom atomics wrapper to substantially improve codegen

kern: use 13.0.0 revised KLightLock logic

kern: fix capability check for thread priorities

kern: remove spurious assertion

kern: update scheduler for 13.0.0 change, fix some ctz/clz bugs

kern: fix use of plr vs plr_heap, fix close/unlock order in ArbitrateLock

ams-libs: move -Wno-invalid-offsetof to cxxflags, not cflags

ams-libs: use nintendo_nx identifier for source file compat bpmp<->ccplex

lr: fix EraseRedirection hang introduced by refactoring

ams: improve offsetof style consistency

util: improve (and use) offsetof that's """standard compliant"""

constexpr: resign ourselves to gcc dropping void -> T support

kern: remove need for explicit reserved member in KAutoObject

kern: devirtualize KAutoObject::DynamicCast<>() ...

This is an optimization that saves the most common type of virtual call in the kernel (DynamicCast)
by storing class token as a member, rather than getting it via virtual call every time.

This does not currently cost any memory space on 64-bit targets, due to pre-existing padding space.

This optimization can be turned off via a compile-time flag for accuracy.

kern/util: update structure layouts to match Nintendo (saves 0x10 per KThread/KSession)

fusee: accept non-zero rather than rejecting non-one for emummc enable

powctl: remove unused arm_neon header after last commit

powctl: don't require arm64 arch for floating -> fixed conversion

git subrepo push libraries ...

subrepo:
  subdir:   "libraries"
  merged:   "cf765c094"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "cf765c094"
git-subrepo:
  version:  "0.4.1"
  origin:   "???"
  commit:   "???"

docs: add changelog for 1.2.0