Error 0x80131c08 when attaching debugger to systemd process that uses `PrivateTmp=true`

## Environment data
VS Code version: 1.38.1
C# Extension version: 1.21.2

## Steps to reproduce
I'm trying to attach debugger via ssh to ASP.NET Core app (.NET Core 3.0 preview9) running on Ubuntu 18.04 x64 under systemd.

systemd service config:
```
[Unit]
Description=TechWiz.Admin.Api service

[Service]
ExecStart=/home/dotnet/dotnet /home/thedensmoke/techwiz_admin_api/TechWiz.Admin.Api.dll
WorkingDirectory=/home/thedensmoke/techwiz_admin_api
User=thedensmoke
Group=thedensmoke
Restart=always
RestartSec=10
SyslogIdentifier=techwiz_admin_api
PrivateTmp=true

[Install]
WantedBy=multi-user.target
```
## Expected behavior
Debugger attach

## Actual behavior
Error 0x80131c08

Same error when attaching with Visual Studio 2019 16.3.0 preview 3.0

Debugger attaches and works well if I launch app on remote host in bash typing `/home/dotnet/dotnet /home/thedensmoke/techwiz_admin_api/TechWiz.Admin.Api.dll`

## Work around
*Note: adding by gregg-miskelly*
Disable `PrivateTmp=true`