Implement support for page sizes > 4KB (#4252)

* Implement support for page sizes > 4KB

* Check and work around more alignment issues

* Was not meant to change this

* Use MemoryBlock.GetPageSize() value for signal handler code

* Do not take the path for private allocations if host supports 4KB pages

* Add Flags attribute on MemoryMapFlags

* Fix dirty region size with 16kb pages

Would accidentally report a size that was too high (generally 16k instead of 4k, uploading 4x as much data)

Co-authored-by: riperiperi <rhy3756547@hotmail.com>

ARMeilleure/Memory/IJitMemoryAllocator.cs

@@ -4,5 +4,7 @@
     {
         IJitMemoryBlock Allocate(ulong size);
         IJitMemoryBlock Reserve(ulong size);
+
+        ulong GetPageSize();
     }
 }