Using `async`/`await` with ember-browserify installed causes build errors

[Kerrick]

You can see this issue in a reduced test case in this repository. In the commit where I generate an async function that does not get compiled, ember s works great. But after this commit where I install ember-browserify, ember s fails to build.

kerrick@alakazam:~/Temporary/browserify-issue$ npm -v
n3.10.10
kerrick@alakazam:~/Temporary/browserify-issue$ node -v
v6.10.2
kerrick@alakazam:~/Temporary/browserify-issue$ ember -v
ember-cli: 2.13.3
node: 6.10.2
os: linux x64
kerrick@alakazam:~/Temporary/browserify-issue$ ember s
Could not start watchman
Visit https://ember-cli.com/user-guide/#watchman for more info.
Livereload server on http://localhost:49154
'instrument' is imported from external module 'ember-data/-debug' but never used
The Broccoli Plugin: [object Object] failed with:
Error: Build Canceled: Broccoli Builder ran into an error with StubGenerator plugin. 💥
    at new BroccoliBuildError (/home/kerrick/Temporary/browserify-issue/node_modules/broccoli-builder/lib/broccoli-build-error.js:40:9)
    at /home/kerrick/Temporary/browserify-issue/node_modules/broccoli-builder/lib/builder.js:168:19
    at tryCatch (/home/kerrick/Temporary/browserify-issue/node_modules/rsvp/dist/rsvp.js:539:12)
    at invokeCallback (/home/kerrick/Temporary/browserify-issue/node_modules/rsvp/dist/rsvp.js:554:13)
    at publish (/home/kerrick/Temporary/browserify-issue/node_modules/rsvp/dist/rsvp.js:522:7)
    at publishRejection (/home/kerrick/Temporary/browserify-issue/node_modules/rsvp/dist/rsvp.js:457:3)
    at flush (/home/kerrick/Temporary/browserify-issue/node_modules/rsvp/dist/rsvp.js:2414:5)
    at _combinedTickCallback (internal/process/next_tick.js:73:7)
    at process._tickCallback (internal/process/next_tick.js:104:9)

The broccoli plugin was instantiated at: 
undefined

The issue seems to be in parseEs6.

[stefanpenner]

should be fixed in v1.1.14