Move partial unmap handler to the native signal handler (#3437)

* Initial commit with a lot of testing stuff.

* Partial Unmap Cleanup Part 1

* Fix some minor issues, hopefully windows tests.

* Disable partial unmap tests on macos for now

Weird issue.

* Goodbye magic number

* Add COMPlus_EnableAlternateStackCheck for tests

`COMPlus_EnableAlternateStackCheck` is needed for NullReferenceException handling to work on linux after registering the signal handler, due to how dotnet registers its own signal handler.

* Address some feedback

* Force retry when memory is mapped in memory tracking

This case existed before, but returning `false` no longer retries, so it would crash immediately after unprotecting the memory... Now, we return `true` to deliberately retry.

This case existed before (was just broken by this change) and I don't really want to look into fixing the issue right now. Technically, this means that on guest code partial unmaps will retry _due to this_ rather than hitting the handler. I don't expect this to cause any issues.

This should fix random crashes in Xenoblade Chronicles 2.

* Use IsRangeMapped

* Suppress MockMemoryManager.UnmapEvent warning

This event is not signalled by the mock memory manager.

* Remove 4kb mapping

Ryujinx.Memory/MemoryAllocationFlags.cs

@@ -35,12 +35,6 @@ namespace Ryujinx.Memory
         /// Indicates that the memory block should support mapping views of a mirrorable memory block.
         /// The block that is to have their views mapped should be created with the <see cref="Mirrorable"/> flag.
         /// </summary>
-        ViewCompatible = 1 << 3,
-
-        /// <summary>
-        /// Forces views to be mapped page by page on Windows. When partial unmaps are done, this avoids the need
-        /// to unmap the full range and remap sub-ranges, which creates a time window with incorrectly unmapped memory.
-        /// </summary>
-        ForceWindows4KBViewMapping = 1 << 4
+        ViewCompatible = 1 << 3
     }
 }