Deprecate before observers

Also remove usages of public `addBeforeObserver` in ember internals.
Cleanup repeated `ember-testing` test setup

Extracts Ember Test Helper setup into `setup` blocks. Rearranges
tests to better leverage `Qunit.module` setup.

Extracts repeated calls to

```js
run(function() {
  App = EmberApplication.create();
  App.setupForTesting();

  App.injectTestHelpers();
});
```
Removes unnecessary resolution
Merge pull request #9815 from twokul/bower-hbs-2

Removes unnecessary resolution
Update tooling for HTMLBars compiler/syntax package split.
Attributes are previously concatted, do not concat again.
Ensure view bindings flush via runloop
Merge pull request #9816 from tomdale/htmlbars-bindings-runloop

[BUGFIX] Ensure view bindings flush via runloop
Move concat into hooks module
Use AST builders in each/with transforms
Switch attribute bindings to diffing strategy
Bump HTMLBars version to 0.4.0.
Remove ConcatAttrNode.
Merge pull request #9817 from emberjs/update-htmlbars-part-500000

Update HTMLBars to 0.4.0.
Merge pull request #9802 from seanpdoyle/test-helpers-cleanup

Cleanup repeated `ember-testing` test setup
[BUGFIX beta] Route.send is unit testable

this.router doesn’t exist when unit testing
Ember.Route, and hence .send breaks all the time;
this change allows you to unit test routes and
their actions even when this.router is absent.

/cc @rwjblue
Merge pull request #9820 from machty/route-unit-test-send

[BUGFIX beta] Route.send is unit testable
Enable HTMLBars & Block Params.

All `Ember.HTMLBars` API surface is private for 1.10, they are still
somewhat experimental.
Remove deprecation notices for Ember.Handlebars functions.

Will add back when we are confident on HTMLBars versions.
Merge pull request #9824 from rwjblue/enable-htmlbars

Enable HTMLBars & Block Params.