Describe the bug

github.Workspace and runner.Workspace don't point to container valid paths when executing inside a container job.

The values are also inconsistent with the values for env variables GITHUB_WORKSPACE and RUNNER_WORKSPACE (both contain a valid path.

To Reproduce
Steps to reproduce the behavior:

1. Create a workflow with the following jobs

jobs:
  runner:
    runs-on: ubuntu-latest

    steps:
      - name: dump
        run: |
          echo 'github.workspace === ${{ github.workspace }}'
          echo "GITHUB_WORKSPACE === $GITHUB_WORKSPACE"
          echo 'runner.workspace === ${{ runner.workspace }}'
          echo "RUNNER_WORKSPACE === $RUNNER_WORKSPACE"
  container:    
    runs-on: ubuntu-latest
    container:
      image: node:14.16
      
    steps:
      - name: dump
        run: |
          echo 'github.workspace === ${{ github.workspace }}'
          echo "GITHUB_WORKSPACE === $GITHUB_WORKSPACE"
          echo 'runner.workspace === ${{ runner.workspace }}'
          echo "RUNNER_WORKSPACE === $RUNNER_WORKSPACE"

2. Check the value in the container job for ${{ github.workspace }} and $GITHUB_WORKSPACE which are not the same
3. Check the value in the container job for ${{ runner.workspace }} and $RUNNER_WORKSPACE which are not the same

Expected behavior

On the container job github.workspaceand runner.workspace should point to a path in the directory /__w

Runner Version and Platform

Version of your runner? 2.295.0

OS of the machine running the runner? ubuntu 20.04.4 (ubuntu-latest)

What's not working?

The values for github.workspace and runner.workspace are incorrect in the container job (and inconsistent with respective env variables)

Job Log Output

If applicable, include the relevant part of the job / step log output here. All sensitive information should already be masked out, but please double-check before pasting here.

Output of container dump step in the container job

github.workspace === /home/runner/work/testContainers/testContainers
GITHUB_WORKSPACE === /__w/testContainers/testContainers
runner.workspace === /home/runner/work/testContainers
RUNNER_WORKSPACE === /__w/testContainers

Runner and Worker's Diagnostic Logs

If applicable, add relevant diagnostic log information. Logs are located in the runner's _diag folder. The runner logs are prefixed with Runner_ and the worker logs are prefixed with Worker_. Each job run correlates to a worker log. All sensitive information should already be masked out, but please double-check before pasting here.