== should normalize the nested instruction ==
ONBUILD   RUN    echo hello
ONBUILD  COPY   --chown=user:group   src   dest
ONBUILD   ADD . /app/src

[expect]
ONBUILD RUN echo hello
ONBUILD COPY --chown=user:group src dest
ONBUILD ADD . /app/src

== should normalize a nested exec form ==
ONBUILD  CMD   [  "echo"  ,  "hi"  ]

[expect]
ONBUILD CMD ["echo", "hi"]
