Prior to Windows 7, the undocumented NtQuerySystemInformation API did
not return valid handle information when called by a WOW64 process. To
work around this problem, the 32-bit test program connects to a 64-bit
worker and uses the existing RPC mechanism, issuing LookupKernelObject
commands, which call NtQuerySystemInformation in a native 64-bit
environment.
Even on Windows 7, the NtQuerySystemInformation API returns truncated
kernel object pointers, so, AFAIK, we still need to do this work. Maybe
not, though, if the lower 32 bits are guaranteed to be unique.
On Windows 10, there is a CompareObjectHandles API that works in WOW64
mode.
* Also add a public Worker::exit() for killing workers more conveniently.
* Previously, a Worker was either:
(1) fully initialized and running (m_valid==true), or
(2) moved out of (m_valid==false)
Now RemoteWorker::trySpawn() can return an invalid RemoteWorker object.
