When partially releasing memory on large pages we 
(1) perform PartialRelease on the region at the end of the page
(2) decrease the page size

On Windows this is problematic because we cannot actually release the region but merely uncommit it due to Windows API constraints. Furthermore, we should update the committed counter on LargeObjectSpace to reflect that memory was uncommitted, as this counter is reported.

The address space leak happens when we then finally release the large page as we only release and update the counters corresponding to the page size.

To address this issue we need to
(a) report the uncommitted area right away, and
(b) release the right region of memory when fully returning the page