Test various directory lookup APIs in different SKUs

### Description

Based on some reports of incorrect behavior across different SKUs when using different directory lookup APIs, we should capture the current behavior, ensure we have validation and track any required future work to fix problems when we can introduce breaking changes.

Some of the APIs that may return unexpected results (e.g., the path to the standby functions) are:

- `Directory.GetCurrentDirectory()`
- `Environment.CurrentDirectory` (impacts the above)
- `IHostingEnvironment.ContentRootPath` (this is a known problem in some of the Linux environments)

We need to validate the above (and other .NET path resolution APIs) across supported SKUs, with and without placeholder (native .NET placeholder).

### Steps to reproduce

Create a Function using the mentioned APIs and capture the output.

Create a Function that reports Directory.GetCurrentDirectory(), Environment.CurrentDirectory, IHostingEnvironment.ContentRootPath, and other .NET path-resolution APIs. Run it across supported SKUs with and without the native .NET placeholder, capture the outputs, and document current behavior plus any future fixes needed.

Written by the indexing model from the issue text.