Use ember-try to hack around qunit nodetests issue.

Add an ember:try configuration for running nodetests. In it,
remove the ember-cli-qunit dependency from the project, so that
the generator test can successfully run with its faked-out
dependency instead of finding the *actual* project dependency.

Update Travis and AppVeyor configs to use the ember-try scenario
instead of running `nodetest` directly.

Author: chriskrycho

.travis.yml

@@ -35,10 +35,10 @@ install:
 
 script:
   - yarn lint:js
+  - yarn ember try:one integrated-node-tests
   # Usually, it's ok to finish the test scenario without reverting
   #  to the addon's original dependency state, skipping "cleanup".
-  - node_modules/.bin/ember try:one $EMBER_TRY_SCENARIO --skip-cleanup
-  - yarn run nodetest
+  - yarn ember try:one $EMBER_TRY_SCENARIO --skip-cleanup
 
 # We build PRs, but don't trigger separate builds for the PR from the branch.
 branches:

appveyor.yml

@@ -28,7 +28,7 @@ test_script:
   # Output useful info for debugging.
   - yarn versions
   - cmd: yarn ember try:one ember-release
-  - cmd: yarn run nodetest
+  - cmd: yarn ember try:one integrated-node-tests
 
 # Don't actually build.
 build: off

config/ember-try.js

@@ -1,6 +1,15 @@
 module.exports = {
   useYarn: true,
   scenarios: [
+    {
+      name: 'integrated-node-tests',
+      command: 'yarn nodetest',
+      npm: {
+        devDependencies: {
+          'ember-cli-qunit': null,
+        },
+      },
+    },
     {
       name: 'ember-lts-2.12',
       npm: {

package.json

@@ -68,6 +68,7 @@
     "ember-cli-htmlbars": "^2.0.1",
     "ember-cli-htmlbars-inline-precompile": "^1.0.0",
     "ember-cli-inject-live-reload": "^1.4.1",
+    "ember-cli-qunit": "^4.3.0",
     "ember-cli-release": "^0.2.9",
     "ember-cli-shims": "^1.2.0",
     "ember-cli-sri": "^2.1.0",