Don't try to match lifted equality operators on same reference types
Nested partial type inside generic class can have base type defined later than current type inflation happens. Fixes #13289
Add nested partial types inside nested partial types to AST. Fixes #13316
Simplify emit_write_barrier().

We have two ways of passing in the value - by MonoInst* and by register.
Remove the second and always pass a MonoInst*.
Avoid calling mono_domain_free () in a cross-compiler, it causes a GC, and the unwind infrastructure is not properly set up when cross-compiling.