These helpers haven't been used in production code since segwit was
merged more than eight years ago (see commit 605e8473, PR #8149),
so it seems appropriate to move them to the test utils module.
Can be reviewed via `--color-moved=dimmed-zebra`.
In order to ensure that the change of nVersion to a uint32_t in the
previous commit has no effect, rename nVersion to version in this commit
so that reviewers can easily spot if a spot was missed or if there is a
check somewhere whose semantics have changed.
The only difference between SetupDummyInputs() in test/transaction_tests.cpp
and the one in bench/ccoins_caching.cpp was the nValue amounts of the outputs,
so we allow to pass those in an extra (fixed-size) array parameter.