Add --runInBand flag to jest for collecting test data.

[teesloane]

Requested:

Could we add the --runInBand flag to the example config for jest tests: https://circleci.com/docs/2.0/collect-test-data/#jest . A ticket brought this up, as we ask users to add it, but do not provide it in the example.

[michelle-luna]

can you add the person who made this request as a reviewer? thanks!