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
5143d52d2b