8386546: Fix race when reserving memory with NUMA interleaving on Windows

[roberttoyonaga]

Summary

Previously on Windows Hotspot used the following race-y pattern to reserve a virtual memory region and divide it up among NUMA nodes:

• Reserve a large region in order to get an available address range.
• Release the entire range
• Quickly re-reserve subregions within the original region (assigning each to a round robin of NUMA nodes).
  See allocate_pages_individually.

VirtualAlloc2 (available since Windows version 1803) removes the need for this race-y code by introducing "placeholders". Placeholders allow for reserving regions, and later splitting them up while still holding the reservation.

This is a scoped-down version of JDK-8376561 and #30270 limited to the changes required to eliminate the NUMA race. This is the 2nd change in a series of changes that take advantage of VirtualAlloc2 to replace races in Windows code. The preceding change was JDK-8385586.

Divergences from JDK-8376561 / #30270 :

1. The os:: Placeholder API has been moved into os::win32:: in order to constrain the scope of changes to Windows code only.
2. Tests have been moved from test_os.cpp to test_os_windows.cpp

Notes

reserve_placeholder_memory, split_memory, and convert_to_reserved could have been made internal helper functions in os_windows.cpp. However, I added them to os::win32:: so that they could be unit tested better.

Testing:

• Added new tests to os_windows.cpp
• make test TEST=gtest:os
• Tier 1
  Tested locally on Windows.

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Progress

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Issue

• JDK-8386546: Fix race when reserving memory with NUMA interleaving on Windows (Enhancement - P4)

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