Mostly, removing things that were never intended to be exported publicy.
BREAKING CHANGE:
The following are no longer publicly exported APIs. They were intended as internal
utilities and you should use your own util:
```
browserDetection,
dispatchEvent,
el,
normalizeCSS,
stringifyElement,
expect (and custom matchers for Jasmine)
```
This lets users continue using runtime-sideeffect Decorators if they choose,
only down-leveling the marked ones to Annotations.
Also remove the "skipTemplateCodegen" option, which is no longer needed
since Angular compiles with tsc-wrapped rather than ngc. The former doesn't
include any codegen.