"CORSCredentials": true in local.settings.json not working for local development

Adding the CORSCredentials setting to true in local.settings.json; does not appear to result in Access-Control-Allow-Credentials: true, header being added to the HTTP Response even when a valid Origin is passed, and the proper Access-Control-Allow-Origin is returned.

The following is what I have in my local.settings.json:
```
{
"IsEncrypted": false,
"Values": {
"FUNCTIONS_WORKER_RUNTIME": "node"
},
"Host": {
"CORS": "http://localhost",
"CORSCredentials": true
},
"ConnectionStrings": {}
}
```
I'm running version 2.0.3 of the runtime, and utilizing NodeJS.

This is an example HTTP Request to my application:
```
GET /api/getCSRF HTTP/1.1
Host: localhost:7071
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Origin: http://localhost
Connection: close
Referer: http://localhost/
Cache-Control: max-age=0
```
and the HTTP Response I'm getting from the local function runtime:
```
HTTP/1.1 200 OK
Connection: close
Date: Tue, 09 Jun 2020 20:23:37 GMT
Content-Type: application/json; charset=utf-8
Server: Kestrel
Set-Cookie: CSRFToken=bbcb_TRUNCATED_ddef; secure; HttpOnly
Access-Control-Allow-Origin: http://localhost
Content-Length: 87

{
"CSRFToken": "e23169a5902139e477b942cb3e171284b3fbf46911e41a4bb50814fbd297b1df"
}
```
I have not yet attempted this on the live Azure Functions, but I will soon and will update here.

Start by reproducing the issue with the provided local.settings.json on Azure Functions Core Tools 2.0.3, using an HTTP request with Origin: http://localhost. Trace how the local runtime handles Host.CORSCredentials and verify that a successful result includes Access-Control-Allow-Credentials: true alongside the appropriate Access-Control-Allow-Origin header.

Written by the indexing model from the issue text.