'then' not changing input source

[willr3]

qDup commands default to getting their input from the previous command

- sh: createJson.sh
- json: $.access.key.in.json
- set-state: storeKey

This default "flow" should change from previous command to parent command when "then" is used

- sh: createjson.sh
  then:
  - json: $.access.first.key
    then:
    - set-state: firstKey
  - json: $.access.second.key
    then:
    - set-state: secondKey
- set-state: alJson

but right now $.access.second.key is getting the output of $.access.first.key as it's input instead of the output of createJson.sh
Fixing this will likely appear as a breaking change to any script that was relying on commands under then to still get their input from the previous command instead of the command but this fix is necessary to support the example above.

[willr3]

If we change the input source to be the parent if the command is under a then it breaks 2 existing tests and introduces some edge cases.

Broken tests:

• io.hyperfoil.tools.qdup.RunTest#echo_exit_status
• io.hyperfoil.tools.qdup.cmd.NannyTest#self_finishing_repeat_until

Edge cases:
We can filter out parents that are instances of Script because those are top level commands in the script and they should receive input from the previous command, not the parent. The next issue is the LoopCmd commands.

- repeat-until:
  then:
  - sh: doSomething.sh
  - regex: <findSomething>

In the current behavior the regex will work on the ouptut of doSomething.sh but the proposed change would have the regex getting input from the repeat-until. The LoopCmd do not create their own output so regex would receive what output was passed into repeat-until.

1. We can tell users they must use then to direct output after the first use of then:

- repeat-until:
  then:
  - sh: doSomething.sh
    then:
    - regex: <findSomething>

2. We can have the then cascading exclude LoopCmd This would leave the repeat-until scenario unchanged (and also for-each) and would only change the input source for optional then.
3. Another option is to only change the input source for then on a command that generates new outout. This would be sh, exec, parse, json, ... (I'm not sure of all of them right now).

I'm not particularly fond of approach 3. because I believe it would introduce too much confusion on the effect of then. I also think approach 2. is going to cause confusion but at least there we can differentiate on the then being required for repeat-until and for-each so it does not change the default input source.