Adds protect_env and admin_stubs to disable-able emulator features

[abeisgoat]

No description provided.

[coveralls]

Coverage increased (+0.01%) to 60.604% when pulling 82e952f on ah-emulator-suite into 1befc99 on master.

[samtstern]

I tried to run this on the firebaseopensourcerepo which has a PubSub function and got:

⚠  Error: process.env.GCLOUD_PROJECT is not set.
    at TopicBuilder (/Users/samstern/Projects/firebaseopensource.com/functions/node_modules/firebase-functions/lib/providers/pubsub.js:43:19)
    at Function.get (/Users/samstern/Projects/firebaseopensource.com/functions/node_modules/firebase-functions/lib/cloud-functions.js:156:17)
    at extractTriggers (/Users/samstern/Projects/firebase-tools/lib/extractTriggers.js:7:54)
    at /Users/samstern/Projects/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:481:38
    at Generator.next (<anonymous>)
    at /Users/samstern/Projects/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:7:71
    at new Promise (<anonymous>)
    at __awaiter (/Users/samstern/Projects/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:3:12)
    at main (/Users/samstern/Projects/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:441:12)
    at Object.<anonymous> (/Users/samstern/Projects/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:527:5)
⚠  Your function was killed because it raised an unhandled error.

I think this has to do with the env changes.

[samtstern]

See comment about crash.

[samtstern]

Abes fixed all my local crashes.