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.
This ensures we run in a clean directory, using our real distribution. It finds bugs like @internal
APIs needed to type-check in the offline compiler, as well as problems in package.json.
Also move tsc-wrapped under tools/@angular
Alex Eagle
Victor Berchet