TestComponentBuilder now lives in core/testing. compiler/testing contains a private
OverridingTestComponentBuilder implementation which handles the private behavior
we need to override templates. This is part of the effort to simplify the testing
imports and hide compiler APIs.
Closes#9585
BREAKING CHANGE:
`TestComponentBuilder` is now imported from `@angular/core/testing`. Imports
from `@angular/compiler/testing` are deprecated.
Before:
```
import {TestComponentBuilder, TestComponentRenderer, ComponentFixtureAutoDetect} from '@angular/compiler/testing';
```
After:
```
import {TestComponentBuilder, TestComponentRenderer, ComponentFixtureAutoDetect} from '@angular/core/testing';
```
a33195dcf3