Add e2e autoscaler test for nested remote functions with IdleTimeOut

[mimiliaogo]

Why are these changes needed?

Add an end-to-end test for ray-project/ray#48519.

Specifically, add a nested remote function test:

1. Make sure the autoscaler won't kill a node with blocking workers (i.e, total_resources == available_resources but idle duration = 0). This can happen when the parent node is in a blocking state waiting for its child task on another node to finish.
2. Autoscaler can downscale node when idle duration > idleTimeOut

Note: Since we're not using the latest Ray image here, this test will fail as expected.
ray-project/ray#48519 should fix this.

Related issue number

Closes #2568

Checks

• I've made sure the tests are passing.
• Testing Strategy
  • Unit tests
  • Manual tests
  • This PR is not tested :(

[andrewsykim]

cc @ryanaoleary