Enable large address space optimization on windows.
Fixes #12576 (closed)
This is possible on Windows 8.1 and newer:
https://devblogs.microsoft.com/oldnewthing/?p=93181#comment-1230851
https://devblogs.microsoft.com/oldnewthing/20160701-00/?p=93785
In particular:
Starting in Windows 8.1 and Windows Server 2012 R2, it’s cheap to reserve a lot of virtual address space. No major memory allocation or other charges occur until you start committing pages, in which case the memory requirements are proportional to the amount of address space you commit, rather than the amount of address space you reserve.
Given that Windows 8.1/Server 2012 are the oldest windows version supported by MS this seems acceptable.