Allow more configurability in production builds.

```
DISABLE_ES3=true DISABLE_JSHINT=true DISABLE_MIN=true ember serve --environment=production
```

Takes initial production build time from 70s to 21s, and rebuilds from
6s to 2s.
Merge pull request #9391 from rwjblue/more-configurability-for-prod-builds

Allow more configurability in production builds.
[FEATURE ember-testing-pause-test] Add a helper to pause a test
Remove check for ember-testing-route-helpers feature flag in tests
* Feature flag is not referenced anywhere else
Merge pull request #9393 from kategengler/remove-unused-feature-flag-in-tests

Remove check for ember-testing-route-helpers feature flag in tests, it appears unused
[BUGFIX beta] Make mandatory setter more helpful.
Merge pull request #9383 from kategengler/never-ending-promise

Add pauseTest test helper
Merge pull request #9392 from rwjblue/improve-mandatory-setter-assertion

[BUGFIX beta] Make mandatory setter more helpful.
[BUGFIX beta] Bump HTMLBars to fix IE9 issues
[BUGFIX beta] Assert state of DOM for property changes instead of using jQuery
Remove code-climate complains
Merge pull request #9396 from mixonic/ie9

[BUGFIX beta] IE9 Fixes
Merge pull request #9397 from cibernox/clean_brocfile

Remove code-climate complains in brocfile
Make blockHelperMissing a no-op

In Handlebars 2.0, blockHelperMissing is only used for Mustache compatibility.
Merge pull request #9402 from mmun/noop-block-helper-missing

Make blockHelperMissing a no-op
[DOC beta] Fix isEmpty description
Merge pull request #9404 from cxfree/isempty-description-fix

[DOC beta] Fix isEmpty description
Remove DAG implementation.

As of https://github.com/emberjs/ember.js/pull/5677 the DAG is pulled in
from Bower, this file is no longer needed.
Refactor Ember.platform.

Split various polyfils into separate files.  This will ultimately be
pulled into 1.8 beta series.
[BUGFIX beta] Only tests mandatory-setter in ES5 browers.