Merge bitcoin/bitcoin#25320: util: modify Win32LockedPageAllocator to query windows for limit.

1cb42aeda3 util: modify Win32LockedPageAllocator to query windows for limit (Oskar Mendel)

Pull request description:

  This PR resolves a todo within the Win32LockedPageAllocator: `// TODO is there a limit on Windows, how to get it?`.
  The idea is to use the Windows API to get the limits like the posix based allocator does with `getrlimit`.

  I use [GetProcessWorkingSetSize](https://docs.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-getprocessworkingsetsize) to perform this task and fallback to `return std::numeric_limits<size_t>::max();` just like the posix implementation does.

ACKs for top commit:
  sipsorcery:
    tACK 1cb42aeda3.

Tree-SHA512: 7bdd8a57a4e64ee59d752417a519656e03526878462060753be4dce481eff4889fb5edc1bdbd575b707d9b2dfe255c87da9ef67baac97de9ac5e70a04c852081

src/support/lockedpool.cpp

@@ -202,7 +202,10 @@ void Win32LockedPageAllocator::FreeLocked(void* addr, size_t len)
 
 size_t Win32LockedPageAllocator::GetLimit()
 {
-    // TODO is there a limit on Windows, how to get it?
+    size_t min, max;
+    if(GetProcessWorkingSetSize(GetCurrentProcess(), &min, &max) != 0) {
+        return min;
+    }
     return std::numeric_limits<size_t>::max();
 }
 #endif