Start running tests on Node.js v12. (#2983)

* Start running tests on Node.js v12.

While not currently a so-called "Long-Term-Support" (LTS) release, Node.js
v12 is on target to become LTS in October 2019 and Node.js 8 will end LTS
earlier than previous even-numbered Node.js releases.

See the Node.js schedule: https://github.com/nodejs/Release#release-schedule

With that only a few months away, it's time to start getting a read on
whether we're going to pass tests in that new engine.

* Remove `meteor-promise` and `fibers`, which appear to be unused entirely.

While originally introduced in
#92 to accommodate
Meteor, it seems that we're no longer making `Promise`s Fiber-aware using
the `meteor-promise` library which leverages `fibers` under-the-hood.

Since this package seems to be the sole reason that bootstrapping is failing
on Node.js 12.  To support Node.js 12, we could update to `fibers@4` which
accommodates changes to the V8 API which have been made in recent Node.js
versions, the `fibers@4` implementation is only compatible with Node.js 10
and 12 and is incompatible with Node.js 8, which we still actively support
(though not for much longer!).

.circleci/config.yml

@@ -65,14 +65,17 @@ jobs:
     docker: [{ image: 'circleci/node:8' }]
     <<: *common_test_steps
 
-  # NODE: Note certain tests are currently being skipped for Node.js 10.
   Node.js 10:
     docker: [{ image: 'circleci/node:10' }]
     <<: *common_test_steps
 
+  Node.js 12:
+    docker: [{ image: 'circleci/node:12' }]
+    <<: *common_test_steps
+
   # Other tests, unrelated to typical code tests.
   Linting:
-    docker: [{ image: 'circleci/node:8' }]
+    docker: [{ image: 'circleci/node:10' }]
     steps:
       # (speed) Intentionally omitted, unnecessary, run_install_desired_npm.
       - checkout
@@ -99,5 +102,7 @@ workflows:
           <<: *ignore_doc_branches
       - Node.js 10:
           <<: *ignore_doc_branches
+      - Node.js 12:
+          <<: *ignore_doc_branches
       - Linting:
           <<: *ignore_doc_branches

package.json

@@ -74,7 +74,6 @@
     "@types/body-parser": "1.17.0",
     "@types/connect": "3.4.32",
     "@types/fast-json-stable-stringify": "2.0.0",
-    "@types/fibers": "0.0.30",
     "@types/graphql": "14.2.2",
     "@types/hapi": "17.8.6",
     "@types/ioredis": "4.0.12",
@@ -106,7 +105,6 @@
     "deep-freeze": "0.0.1",
     "express": "4.17.1",
     "fastify": "1.14.6",
-    "fibers": "3.1.1",
     "form-data": "2.4.0",
     "graphql": "14.4.1",
     "graphql-subscriptions": "1.1.0",
@@ -125,7 +123,6 @@
     "lerna": "3.13.4",
     "lint-staged": "8.2.1",
     "memcached-mock": "0.1.0",
-    "meteor-promise": "0.8.7",
     "mock-req": "0.2.0",
     "multer": "1.4.1",
     "node-fetch": "2.3.0",