Fix "Fork, Conditional Jump, Encodings" test and fix the "Return" operation.

[tlwr]

The return operation was setting state.progress to the length of the recipe.

Under async this is incorrect behaviour because after any flow control operation the Recipe executes state.progress + 1, and then at the beginning of the recursed Recipe.execute checks the length and returns if currentStep === recipe.opList.length

Return now sets state.progress equal to state.opList.length - 1.

This bug could instead have been fixed by changing finish condition from currentStep === recipe.opList.length to currentStep >= recipe.opList.length to prevent this class of bugs in the future. I'll leave that decision to @n1474335.

Additionally there was a type in the test "Fork, Conditional Jump, Encodings" which was just a missing newline in the input which was required to match the output.

Screenshot of tests passing

[n1474335]

Good spot. I changed currentStep === recipe.opList.length to currentStep >= recipe.opList.length as it seems like a good defensive measure and I can't think of any scenario where it wouldn't be wanted. If such a scenario presents itself in future we can always change it again.