[mono] Introduce MonoMemoryManager to hold memory previously owned by the domain...

[mono] Introduce MonoMemoryManager to hold memory previously owned by the domain (#41754)

* Introduce MonoMemoryManager

* Move things out of the domain

* Update callers

This does *not* handle cases where we call mono_domain_alloc and friends, just direct access to domain->mp etc. As of this, everything is allocated from the default ALC on netcore and the domain on legacy.

* Update locks in domain_alloc functions

* Take correct lock around mp

* Introduce memory manager allocation helpers

* Shorten mono_domain_default_memory_manager

* Add memory_manager alloc nolock variants

* Fix locking

* More use of nolock functions

* Add trailing newline to monovm.h

This is obviously unrelated, but it was causing issues with my sed commands

* mono_memory_manager -> mono_mem_manager

Bit shorter at least, but I can cut it down further if deemed necessary

* Add to msvc build

* Fix mono/mono build

* Fix test failure

Oops

* Remove erroneous returns

* Store domain in memory manager, take domain lock

* Build fixes

* Remove comment

* Free memory manager during domain unload

* C++ fix

* Don't double free

* Remove designated initializer

MSVC C++ fails it seems :(