Fixes #1778

Test Plan

How do we know the code works?

All tests should pass, when using android tests with legacy mode Flank should generate JUnitReport in the results directory, performance metrics file should be created.

This pr is a revert of @piotradamczyk5 change related to performanceMetrics.json creation. I was checking this feature and still works fine.

To test if performanceMetrics.json are created:

1. Run any test case with a physical device for e.g.

device:
    - model: starqlteue
      version: 26

1. Check if the Flank output contains a line about uploading performanceMetrics.json to gcs

 Uploading [performanceMetrics.json] to https://console.developers.google.com/storage/browser/test-lab-v9cn46bb990nx-kz69ymd4nm9aq/2021-04-19_07-59-02.195180_AbIK/matrix_0/...

1. Check if local matrix directories contain performanceMetrics.json

2. Run the same Flank configuration on the current master and compare performanceMetrics.json.

Test results

gcloud:
  app: ./test_runner/src/test/kotlin/ftl/fixtures/tmp/apk/app-debug.apk
  test: ./test_runner/src/test/kotlin/ftl/fixtures/tmp/apk/app-single-success-debug-androidTest.apk
  device:
    - model: starqlteue
      version: 26

flank:
  disable-sharding: true
  output-report: json

1. performanceMetrics.json from this branch link

2. performanceMetrics.json from current master link

Checklist

• Integration tests updated