[Local GC] Remove a number of inclusions of handle table private headers from the...

[Local GC] Remove a number of inclusions of handle table private headers from the VM (dotnet/coreclr#12389)

* Remove inclusions of private handle table headers from the VM

* Add TraceRefCountedHandles to the GC handle table interface

* Fix the Unix build

* Move ValidatePinnedObject to marshalnative.h

Commit migrated from https://github.com/dotnet/coreclr/commit/3a24095610ecaba62495740bf8319ad467af4997