This is in preparation for having other "command changing things" like
redirecting to file and maybe variable substitutions in the arguments.
"On the way" added a
RUNNING "some_command" "--some_flag" "some_value"
to the output encapsulator so that if we run multiple commands, we know what
command was called where.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=219837452
guyben
9ce07db38a