Revert "Allow overwrite Helper instance"
Revert "Allow overwrite Helper instance"

This reverts commit 210d904dcaef20e1f383155deac892be5970fe96.

We revert this because, this allows the instance to persist
through a powershell session across multiple pssa invocations.
This is allows us to reuse the command info cache across
multiple pssa invocations.

juneb/PSScriptAnalyzer,daviwil/PSScriptAnalyzer,PowerShell/PSScriptAnalyzer,dlwyatt/PSScriptAnalyzer