Related to #6902

The update to @zkochan/cmd-shim@3.0.0 in yarn@1.13.0 revealed a dormant bug where Yarn calls cmd-shim on its own shims, creating shims of shims which do not function correctly in PowerShell. This issue mainly affects Windows, although creating shims of shims in Linux is probably not the greatest solution when the original shim could be used instead.

This issue is intended to track the underlying cause of this, and, eventually, a real fix that can replace the workaround in #6954 and allow proper PowerShell shims to be used.