This only happened if the containing project was buggy, ie. you tried
to build a target that has no .do file available anywhere. However, it
resulted in a confusing outcome for that case, where we'd run the wrong
default.do file with the wrong parameters.
Extended an existing test to catch this mistake.
If we failed because:
- target dir doesn't exist
- failed to copy from stdout
- failed to rename $3
We would correctly return error 209, but the target would still be
marked as having been built, so redo-ifchange would not try to build it
next time, beause we forgot to call sf.set_failed() in those cases.
minimal/do worked correctly.
Added a test to catch this in the future.
