[x86/Linux] Enable gcMarkFilterVarsPinned (WIN64EXCEPTIONS) (#11281)

[x86/Linux] Enable gcMarkFilterVarsPinned (WIN64EXCEPTIONS) (#11281)

* [x86/Linux] Enable gcMarkFilterVarsPinned

Do gcMarkFilterVarsPinned() for WIN64EXCEPTIONS

* [x86/Linux] GCInfo : Force this pointer untracked

`this` pointer is now always untracked so we can use pinned flag in tracked lifetimes.
This allows us to make the refs(inside filter) pinned to prevent from double-relocation.

* [x86/Linux] GCInfo : fix comment and formatting

* [x86/Linux] GCInfo : Update

- Force "this" pointer untracked only when "this" is generic context
- Style fixes

* [x86/Linux] GCInfo : remove this_OFFSET_FLAG