feat($compile): set preAssignBindingsEnabled to false by default

Fixes #15350
Closes #15352

BREAKING CHANGE: Previously, $compileProvider.preAssignBindingsEnabled was
set to true by default. This means bindings were pre-assigned in component
constructors. In Angular 1.5+ the place to put the initialization logic
relying on bindings being present is the controller $onInit method.

To migrate follow the example below:

Before:

```js
angular.module('myApp', [])
  .component('myComponent', {
    bindings: {value: '<'},
    controller: function() {
      this.doubleValue = this.value * 2;
    }
  });
```

After:
```js
angular.module('myApp', [])
  .component('myComponent', {
    bindings: {value: '<'},
    controller: function() {
      this.$onInit = function() {
        this.doubleValue = this.value * 2;
      };
    }
  });
```

If you don't have time to migrate the code at the moment, you can flip the
setting back to true:
```js
angular.module('myApp', [])
  .config(function($compileProvider) {
    $compileProvider.preAssignBindingsEnabled(false);
  })
  .component('myComponent', {
    bindings: {value: '<'},
    controller: function() {
      this.doubleValue = this.value * 2;
    }
  });
```
Don't do this if you're writing a library, though, as you shouldn't change
global configuration then.