Change app directory on environment reload request

[AnatoliB]

Some PowerShell apps intermittently fail on Azure complaining about not being able to app content under D:\local\Temp\functions\standby, typically when trying to load modules. The impact seems to be limited to apps that:

• include custom modules into the app content (not using Managed Dependencies); and
• run from package.

This seems to be caused by the PowerShell worker not changing the app directory when handling the environment reload request:

azure-functions-powershell-worker/src/RequestProcessor.cs

Line 345 in ea4aaf7

internal StreamingMessage ProcessFunctionEnvironmentReloadRequest(StreamingMessage request)

The worker must change the current directory to the one specified by the environment reload request.

Until this is fixed, the workaround is to set the WEBSITE_USE_PLACEHOLDER app setting to 0.