Circle CI: Free up space in test_ios_rntester job

Summary:
When Hermes is used, and if it is built from source on Circle CI, the macos executors can run out of storage space.

Earlier, we solved this issue in the iOS unit test jobs by splitting them into build/test pairs. In the case of test_ios_rntester, there is no convenient way to split the job.

Since test_ios_rntester does not require the use of the iOS simulator, we can go ahead and delete it from the image at run time in order to free up some space and allow the job to finish when Hermes is built from source.

Changelog: [Internal]

Reviewed By: cortinico

Differential Revision: D35297994

fbshipit-source-id: a0cddba2fc2900813fecc63eaf23d53e5b8f6e92

.circleci/config.yml

@@ -732,6 +732,13 @@ jobs:
             rm -rf packages/rn-tester/Pods
             cd packages/rn-tester && bundle exec pod install
 
+      # The macOS machine can run out of storage if Hermes is enabled and built from source.
+      # Since this job does not use the iOS Simulator, deleting it provides a quick way to
+      # free up space.
+      - run:
+          name: Delete iOS Simulators
+          command: sudo rm -rf /Library/Developer/CoreSimulator/Profiles/Runtimes/
+
       - run:
           name: Build RNTester
           command: |