CHEF-5287: Use IsWow64Process instead of ENV hash to determine 32-bit pr...

...ocess on 64-bit OS.

A little more background: somehow, it looks like the ENV hash does not have PROCESSOR_ARCHITECTURE set for some users. I can't think of a reason this would be the case -- it's possible that a process started without an environment block (e.g. CreateProcessAsUser or CreateProcessAsLogin) may hit this, or someone otherwise tampering with the environment. The way to avoid this is to simply not rely on ENV, which was probably a poor choice in the first place for the purpose of detecting 32 or 64-bit process.