`UnsafeAccessorAttribute` non-generic support (#86932)

`UnsafeAccessorAttribute` non-generic support (#86932)

* CoreCLR and NativeAOT

* Add UnsafeAccessorAttribute API

* Implement IL generation for all accessor paths

* Implement static/instance field lookup - non-generic

* Implement static/instance method lookup - non-generic

* Defined ambiguity logic with respect to
custom modifiers.
- First pass ignore custom modifiers
- If ambiguity detected, rerun algorithm but
  require precise matching of custom modifiers.
- If there is no clear match throw AmbiguousImplementationException.

* Cleanup memory management confusion
with ILStubResolver.

* Fix non-standard C++

* Remove CORINFO_MODULE_ALLACCESS scope

* Remove enum METHOD_TYPE.

* Update BOTR on TypeDesc