chore(ngc): refactor out tsc-wrapped

This allows angular's build to depend on some extensions, but not on code generation, and breaks a cycle in the angular build
We now merge ts-metadata-collector into tsc-wrapped and stop publishing the former.

modules/@angular/compiler_cli/index.ts

@@ -1,3 +1,3 @@
 export {CodeGenerator} from './src/codegen';
 export {NodeReflectorHost} from './src/reflector_host';
-export {TsickleHost, MetadataWriterHost} from './src/compiler_host';
+export * from 'tsc-wrapped';