We changed the bootstrap order:
1. create NgZone
2. bootstrap ng1 inside NgZone and upgrade ng1 components to ng2 components.
3. bootstrap ng2 with NgZone
Note: Previous footgun behavior was: bootstrap ng2 first to extract NgZone, so that ng1 bootstrap can happen in NgZone. This meant that if ng2 bootstrap eagerly compiled a component which contained ng1 components, then we did not have complete metadata.
the previous demo app was broken and is missing an e2e test.
I fixed the app, but was not able to get protractor to properly test
this app. Julie and I are looking into that. For now I manually verified
that the app works and that the original issue was fixed.
Closes#9244