Espresso does not wait for AndroidX's ListAdapter's by default

### Description

Included `androidx.recyclerview.widget.ListAdapter` performs asynchronous operations in the background. However, Espresso does not appear to be aware of it and thus tests can fail if async list diff is still diffing while Espresso starts inspecting views.

### Steps to Reproduce

1. Download [RecyclerTest.zip](https://github.com/android/android-test/files/3264598/RecyclerTest.zip)
2. Run ExampleInstrumentedTest couple of times, at least one test will fail eventually

### Expected Results

Espresso should wait for built-in ListAdapter to finish diffing

### Actual Results

Espresso does not wait and can fail the test

Download RecyclerTest.zip and run ExampleInstrumentedTest repeatedly to reproduce the intermittent failure. Trace how Espresso synchronizes with androidx.recyclerview.widget.ListAdapter's asynchronous diffing. Done means Espresso waits for the built-in ListAdapter diff to finish and the reproduced test no longer fails intermittently.

Written by the indexing model from the issue text.