Remove dead test code

...which apparently originated as some kind of duplicate of (also, but
potentially leas dead) io/test/stm/.

Change-Id: Iea749b44da2482835a08c6a21b62625836f8b643
second test should be DataOutputStream

...as <https://gerrit.libreoffice.org/#/c/9007/> "cppcheck: multiCondition,
second test should be DataOutputStream" found out for an effective duplicate of
this code that got removed with the previous commit "Remove dead test code."

Change-Id: Ib7b088f065def2d5e954837d22178521f85c49fe