[1822] fix for full_or_turn SELL_AFTER case.

[philcampeau]

Fixes #10026

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Implementation Notes

• Explanation of Change
  The code previously didn't take into account that it would prevent you from selling stock in another corp which had operated only once if you were also the president of that corp. This should fix that by also checking if the bundle.corporation is the @round.current_operator.

I ran a couple of tests, but given its failure the first time, I'd appreciate it if someone else can't take a look and make sure I got it right this time.

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