Regression issue with debug in WSL

[wux5]

Debug in WSL is broken on the latest version 1.19.0, it used to work in v1.18.

• VSCode Version: 1.19.0
• OS Version: Windows 10

Steps to Reproduce:

1. Setup a Typescript project (I guess it has the same issue with any NodeJS project), with a file server.ts

console.log("testing..."); // Set a breakpoint here

2. Configure launch.json with:

{
      "name": "Current TS File",
      "type": "node",
      "request": "launch",
      "useWSL": true,
      "program": "${workspaceFolder}/node_modules/ts-node/dist/_bin.js",
      "args": [
        "${relativeFile}"
      ],
      "cwd": "${workspaceFolder}",
      "protocol": "inspector"
}

3. Open server.ts, press F5 to run
4. Notice the error as attached. Obviously the path of the current file (${relativeFile}) is incorrect, it's supposed to be /src/server.ts, but the log in the debug console shows: \src\server.ts. This worked correctly in the previous version.

Reproduces without extensions: Yes

[weinand]

duplicate of #40256