On Win10, VirtualQueryEx supports querying the x64 part of WOW64
processes. However, on lower OSs it errors past 2/3G. There's no direct
way to retrieve to maximum memory address for processes other than
yourself, but fortunately, VirtualQueryEx sets a distinct error code
when `lpAddress` exceeds the maximum accessible address, so we can just
terminate successfully in that case.
R=mark@chromium.org
BUG=crashpad:20, crashpad:46
Review URL: https://codereview.chromium.org/1376353002 .
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