The retry code path did not filter `ERROR_NOT_SUPPORTED`. Just call the
original function a second time to correctly follow the low privilege
code path.
Calling `Load()` twice for an atomic variable can return different
values each time. This resulted in trying to read the security
descriptor with high privileges, but then not entering the code path to
switch to low privileges when another thread has already done so
concurrently.
Michael Eischer
aneesh-n