homogenize some test-ish code. source lives in testproject. inherit from pants-int

some of our code-meant-for-testing was in 'examples', some was in 'testproject'.
mv */examples/unicode -> */testproject/unicode

add integration tests to exercise commands that have revealed regressions before

Testing Done:
./build-support/bin/ci.sh

Reviewed at https://rbcommons.com/s/twitter/r/508/