Fix setting Path for Windows

ENV['PATH'] is broken after changing path in windows. It replaces Path in Ruby to path with system variables.
That leads to broken recipes that use executables in System32.

Variant 1 is proposed in this pull request is to replace all systemroot variables to new ones.
Variant 2 would be to change ENV['Path'] separately from changing actual path.
Theoretically `PATH` could be specified as lowercase `path`, or mixed case, correct? So we'd need to handle that scenario. Same for `%SystemRoot%` in the environment variable value. And there may be parts of the path that contain other environment variables (e.g. `%systemdrive%`, `%windir%`, `%programfiles%`, etc.).