This commit switches the `deploy-to-firebase.sh` script, that we use for
deploying angular.io to production, from Bash to JavaScript. This makes
the script easier to maintain.
For the same reasons, it also switches the `deploy-to-firebase.test.sh`
script, that we use for testing the `deploy-to-firebase` script, from
Bash to JavaScript (using jasmine as the test runner).
Finally, this commit also updates ShellJS to the latest version to get
better error messages (including the actual error) when `exec()` fails.
NOTE: Before switching the test script to JS, I verified that the new
`deploy-to-firebase.js` script passed the tests with the old
`deploy-to-firebase.test.sh` script.
PR Close#39470
Since 808bd4af4, we are no longer pre-verifying PRs before uploading the build
artifacts to the preview server, thus we no longer need the
`travis-preverify-pr.sh` script or the `GITHUB_TEAM_MEMBERSHIP_CHECK_KEY`
variable.
George Kalpakas
Pete Bacon Darwin