Create core-lambda-stubs from .txt files

APIs to compile lambda are part of art's toolchain api surface.
Generating stubs from .txt files allows us to prune the remaining sdk
dependencies on libcore/ that are not api files

Test: m core-lambda-stubs.from-text
(On top of change containing core.current.stubs.from-text
and turning enabled: true)

Change-Id: I0ab8459b9317cb055a434eb635ba06d38da5b92e