Add some backward compatible code for IsWindows and IsLinux

[harrisonmeister]

We had an internal report about cloning a tentacle instance in the incorrect folder. Presumably, this was on running on Windows PowerShell.

Not a big fan of even having to add this, but it does seem to work.

[CLAassistant]

All committers have signed the CLA.

[BobJWalker]

This looks to be a bit overkill. IsWindows and IsLinux was added in PowerShell Core 6. PowerShell 5.1 and lower wouldn't have those variables. But those versions of PS only run on Windows.

If those variables are not set then it is safe to assume they are running on Windows.

[harrisonmeister]

This looks to be a bit overkill. IsWindows and IsLinux was added in PowerShell Core 6. PowerShell 5.1 and lower wouldn't have those variables. But those versions of PS only run on Windows.

If those variables are not set then it is safe to assume they are running on Windows.

@BobJWalker - I've removed the code I added , and just switched around the one place where testing for $IsWindows was failing to default to Windows.

[BobJWalker]

LGTM